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1
KUMAR, G. SENTHIL, PAKALA SAIDULU, M. DJANAGUIRAMAN, K. SUBRAHMANIYAN, P. PARASURAMAN, and R. MAHENDRA KUMAR. "Exploring drought mitigation options for improvement of physiology, yield and water use efficiency of aerobic rice (Oryza sativa)." Indian Journal of Agricultural Sciences 94, no. 7 (2024): 695–700. http://dx.doi.org/10.56093/ijas.v94i7.143538.
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An experiment was conducted during summer seasons of 2022 and 2023 in Wetland Farms at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu to mitigate the ill effects of moisture stress during the flowering stage of rice (Oryza sativa L.) by moisture stress mitigating chemicals. The trial was laid out in split plot design (SPD) with 3 main plots and 4 sub-plots, and replicated thrice. In main plot, irrigation at IW/CPE ratio 1.0 from emergence to physiological maturity (M1); withholding irrigation (drought stress) for 8 days from heading stage (M2); and withholding irrigation (drought stress) for 12 days from heading stage (M3) and in sub-plot drought stress mitigating chemicals, viz. no spray (S1); salicylic acid spray @100 ppm (S2); sodium selenate @20 ppm (S3); and pink pigmented facultative methylotrophs (PPFM) @1% (S4) were tested. Results revealed that irrigation at IW/CPE 1.0 from crop emergence to physiological maturity along with foliar spray of selenium @20 ppm at heading stage had beneficial impact on growth, physiological parameters, yield attributes and yield. Drought stress given for 8 days from heading stage with selenium spray recorded lesser detrimental effect on growth characters, yield attributes and yield when compared to drought stress given for 12 days from heading stage in aerobic rice cultivation. The yield reduction in drought stress for 12 days from heading stage with selenium @20 ppm spray and drought stress for 8 days from heading stage with selenium @20 ppm spray were 23.6 and 16.5% respectively, when compared to irrigation at IW/ CPE ratio 1.0 from crop emergence to physiological maturity with selenium spray @20 ppm. Water use efficiency and water profitability also increased by the application of stress mitigating chemical of sodium @20 ppm. From this study, it is recommended that, in aerobic rice cultivation if there is any drought occurrence during heading stage of crop, the selenium application @20 ppm can withstand drought even up to 8 days from heading stage.
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Mo, Youngjun, Jong-Min Jeong, Su-Kyung Ha, et al. "Characterization of QTLs and Candidate Genes for Days to Heading in Rice Recombinant Inbred Lines." Genes 11, no. 9 (2020): 957. http://dx.doi.org/10.3390/genes11090957.
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Understanding the gene mechanisms controlling days to heading (DH) is important in rice breeding for adaption in the target environment. Using a recombinant inbred line population derived from the cross between two japonica rice cultivars, Koshihikari and Baegilmi, we identified three consistent quantitative trait loci (QTLs) for DH for two years, qDH3, qDH6, and qDH7 on chromosomes 3, 6, and 7, respectively. While Baegilmi contributed the allele for early heading at qDH6 and qDH7 with the additive effect of five days each, Koshihikari contributed the allele for early heading at qDH3 with the additive effect of three days. Notably, pyramiding two or more alleles for early heading at these QTLs accelerated heading effectively. Sequencing of Hd16, Hd1, and Ghd7, the previously known heading date genes underlying qDH3, qDH6, and qDH7, respectively, revealed that Baegilmi and Koshihikari carry different alleles at the three genes. Molecular markers were developed to screen the allelic compositions of the three genes among 295 Korean commercial rice cultivars. The results showed that few cultivars carry alleles for early heading at the three genes, highlighting that DH can be further accelerated and fine-tuned in breeding programs by combining the desirable alleles of Hd16, Hd1, and Ghd7.
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Hooker, D. C., A. W. Schaafsma, and L. Tamburic-Ilincic. "Using Weather Variables Pre- and Post-heading to Predict Deoxynivalenol Content in Winter Wheat." Plant Disease 86, no. 6 (2002): 611–19. http://dx.doi.org/10.1094/pdis.2002.86.6.611.
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Substantial economic losses have occurred because of unacceptable concentrations of deoxynivalenol (DON) in wheat. Accurate predictions of DON in mature grain at wheat heading are needed to make decisions on whether a control strategy is needed. Our objective was to identify important weather variables, and their timing, for predicting concentrations of DON in mature grain at wheat heading. We measured the concentration of DON in 399 farm fields in southern Ontario, Canada, from 1996 to 2000. DON varied in field samples from undetectable to over 29 μg g-1. Weather variables, such as daily rainfall, daily minimum and maximum air temperatures, and hourly relative humidity, were estimated for each field from nearby weather stations and were normalized to the date of 50% head emergence. Stepwise multiple regression procedures determined the most important weather variables and their timing around heading. DON was responsive to weather in three critical periods around heading. In the first period, 4 to 7 days before heading, DON generally increased with the number of days with >5 mm of rain and decreased with the number of days of <10°C. In the second period, 3 to 6 days after heading, DON increased with the number of days of rain >3 mm and decreased with days exceeding 32°C. In the third period, 7 to 10 days after heading, DON increased with number of days with >3 mm of rain. A relationship between relative humidity and DON was not detected. Overall, 73% of the variation in the concentration of DON was explained by using weather from all three critical periods. Concentrations of DON <2.0 μg g-1 were predicted best; in fact, concentrations of DON of <1.0 μg g-1 were predicted correctly on over 89% of the fields used to train the model.
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Hadjichristodoulou, A. "The effects of optimum heading date and its stability on yield and consistency of performance of barley and durum wheat in dry areas." Journal of Agricultural Science 108, no. 3 (1987): 599–608. http://dx.doi.org/10.1017/s002185960008000x.
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SummaryData from several trials with large numbers of barley and durum wheat varieties conducted mainly under dryland conditions in a Mediterranean climate were used to study the effects of heading date and its stability on consistency of performance.Heading date was expressed in relation to one or more control varieties, because of the significant genotype × environment interactions. Data from trials during 1969–85 were used to determine optimum heading date in order to aid selection for consistently high-yielding varieties. For rainfed barley in Cyprus this optimum range was between 2 days after and 5–8 days before heading of Kantara barley and for rainfed wheat 1 day after to 4 days before heading of Karpasia durum wheat. It is suggested that by selecting at one environment single plants from segregating populations or lines from nurseries and yield trials, having heading date within the optimum range, the chances of selecting consistently high-yielding lines are increased.The genotype and environment significantly affected heading date. Stability of heading date was genetically controlled. Early varieties tended to be more variable than late varieties of both barley and durum wheat. Lines with the lowest values for variance of heading date gave low yields under variable conditions because they were very late. The consistently high-yielding lines of barley and durum wheat had variance of log transformed heading (s2log2) 0·025–0·050.In durum wheat, lines with the lowest variance were later in heading date than the optimum for Cyprus environments. The absolute values of variance of heading date of varieties varied with year, but significant positive correlations were obtained between years (r = 0·84 for durum wheat and r = 0·55 for barley, P < 0·01).Barley, which is considered a safer crop for the driest parts of the Mediterranean countries, heads a few days earlier than durum wheat but its better performance may be attributed also to its ability to grow faster than wheat in the winter months.
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Teng, Mengnan, Xiaoliang Duan, Ru Feng, et al. "Effects of Harvest Time on Grinding Quality, Appearance Quality and Physical and Chemical Quality of Japonica Rice." Foods 13, no. 18 (2024): 2868. http://dx.doi.org/10.3390/foods13182868.
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Harvest time is very important to rice due to its high correlation to rice yield, eating quality, etc.; however, the impact of harvest time on quality is still unclear. In this study, Nangeng 5718, a japonica rice planted in three regions in Jiangsu Province of China, was used to analyze and compare the milling quality, appearance quality, and physicochemical quality of japonica rice at different harvest times. The results showed that the 1000-grain weight of Nangeng 5718 exhibited no significant change at different harvest times (p > 0.05). The brown rice rate and rice yield at different harvest times were 82.3–85.4% and 66.3–76.1%, respectively. Harvest time had no significant effect on the brown of rice (p > 0.05). However, Nangeng 5718 planted in Nanjing had the highest rice yield at 50 days after heading, which was significantly different from that of rice harvested 65 days after heading (p < 0.05). Nangeng 5718 planted in Huai’an had the highest rice yield at 55 days after heading, which was significantly different from that of rice harvested 60 days after heading (p < 0.05). Harvest time had little effect on the length, width, and thickness of rice. The immature grain rate showed a decreasing trend with the increase in maturity. There were little differences in the protein content of Nangeng 5718 at different harvest times. Nangeng 5718 planted in Nanjing had the highest protein content at 50 days after heading. There was a significant difference between the rice harvested and the rice harvested 60 days after heading (p < 0.05). There were no significant differences between the other two regions (p > 0.05). The accumulated temperature in Nanjing was relatively high, and the RVA curve and RVA eigenvalues of rice varied greatly. The setback value of rice harvested at 50 days was significantly lower than that at 55 days and 60 days (p < 0.05). Rice has good gelatinizing properties. Therefore, timely harvesting and appropriate accumulated temperature could increase 1000-grain weight and rice yield, reduce the immature grain rate, and improve the gelatinization characteristics. Overall, the quality of Nangeng 5718 reached a good level when it was harvested 50 days after heading, with the accumulated temperature reaching 1051 °C. In fact, the harvest time should be chosen flexibly according to the weather conditions. Nangeng 5718 planted in Nanjing should be harvested earlier than 50 days, and rice from Huai’an and Lianyungang was of better quality when the harvest time was 50 days.
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Amna Naz, Abdur Rauf, Mamoona Bibi, et al. "Evaluation of Variability, Genetic Advancement and their Correlation in Triticum Aestivum L." Indus Journal of Bioscience Research 2, no. 2 (2024): 58–63. https://doi.org/10.70749/ijbr.v2i02.134.
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The current research was conducted with the objective to estimate evaluation of variability, genetic advance and correlations in wheat. Sixty-four wheat advance lines were grown in alpha lattice designed during 2022-2023 at Cereal Crops Research Institute (CCRI), Pirsabak Nowshera, Pakistan. Significant differences among genotypes were recorded shown through analysis of variance. Days to heading ranged from 116 days to138 days, flag leaf area ranged from 18cm2-40cm2, plant height ranged from 84 cm -111 cm, tiller m-2 ranged from 136-424, grain yield from 3240 kg/ ha to 6051 kg/ ha and thousand grain weight ranged from 31g-52 g. Maximum value of GCV reported for tiller per spike (20.2), while minimum value recorded for days to heading (2.70), while high PCV value recorded for1000 grain weight was (25.02), while lowest value recorded for grain yield (0.27). Magnitude of heritability was higher for grain yield (2358) and it was recorded moderate for thousand grain weight (0.50). Maximum value of genetic gain recorded for tiller-2 (65.38) and it was minimum for days to heading (3.73). The findings indicated strong and positive link between grain yield with plant height (r=0.30**), days to heading have a negative correlation with qualities that contribute to production, such as grain yield and 1000-grain weight.
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Hossen, Putri Ainaa Afiqah, and Hollena Nori. "Reproductive Development and Yield Components of Bario Sederhana Rice in Response to Photoperiod." Malaysian Applied Biology 52, no. 6 (2023): 111–18. http://dx.doi.org/10.55230/mabjournal.v52i6.2690.
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A series of controlled environment treatments were conducted to quantify reproductive development and yield components of Bario Sederhana rice grown under five photoperiod regimes (8, 9, 10, 11, & 12 h). A ‘broken-stick’ linear regression of heading rate against photoperiod was used to determine the cardinal photoperiods for heading. The reproductive development towards photoperiod showed a delayed pattern in time to heading, anthesis, and maturity under lengthening photoperiod from 10 to 12 h. For example, under 10 h photoperiod the crops required 1680 °Cd (70.8 days) from emergence to heading but took an extended duration of 3147 °Cd (132.6 days) when they were sown at 12 h photoperiod. The prolonged time taken for reproductive development modified by photoperiod resulted in higher yield components. This is because the lengthening time from heading to maturity extended the duration of grain filling. The longest photoperiod of 12 h gave the highest percentage of filled spikelets (65.3%) thus consequently leading to the heaviest grain weight of 1.4 g per panicle. The base, optimum, and maximum photoperiod for heading were estimated to be 7.4 h, 10 h, and 14.8 h, respectively.
8
Tashiro, T., and IF Wardlaw. "The effect of high temperature on kernel dimensions and the type and occurrence of kernel damage in rice." Australian Journal of Agricultural Research 42, no. 3 (1991): 485. http://dx.doi.org/10.1071/ar9910485.
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Rice (Oryza sativa L. cv. Calrose) growing at 27/22�C was either transferred to day/night temperatures ranging from 24/19 to 39/34�C 7days after heading and held at these temperatures until maturity, or transferred to a temperature of 36/31�C for 8 day periods at regular intervals commencing from heading. Kernel dimensions were measured directly and the types of kernel damage at maturity were characterized by direct viewing under the light microscope of intact and sectioned kernels, or by scanning electron microscopy of the exposed surface of kernels cut transversely with a razor blade. Kernel thickness was reduced most by high temperature treatments commencing 12 days after heading, but other kernel dimensions (length and width) were most sensitive to high temperature earlier in development. Sterility and pathenocarpy were most evident when temperature treatments commenced at heading (approximately 2 days before anthesis) and were greatest at the highest temperature (39/34�C). Abortive and opaque kernels were most evident when the high temperature commenced 4 days after heading and were also most numerous at the highest temperature tested. From observations on the morphology of the kernels it appears that temperatures above 27/22�C can interfere with the early stages of cell division and development in the endosperm. Chalky endosperm tissue occurred in several forms depending on both the temperature level and the timing of the temperature treatment. White-core kernels were only evident at a temperature of 27/22�C. White-back kernels were most numerous at 36/31�C and when the high temperature treatment commenced 16 days after heading. Milky-white kernels were found in all but the lowest temperature treatment (24/19�C), with a peak at 36/31�C and this type of damage was most evident when the high temperature treatment commenced 12 days after heading. Differences in endosperm cellular morphology were observed between the different types of damage, and in accord with other published data the chalky appearance was associated with the development of numerous air spaces between loosely packed starch granules and a change in light refraction.
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Wu, Qiang, Yongping Zhang, Zhiwei Zhao, Min Xie, and Dingyi Hou. "Estimation of Relative Chlorophyll Content in Spring Wheat Based on Multi-Temporal UAV Remote Sensing." Agronomy 13, no. 1 (2023): 211. http://dx.doi.org/10.3390/agronomy13010211.
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Relative chlorophyll content (SPAD) is an important index for characterizing the nitrogen nutrient status of plants. Continuous, rapid, nondestructive, and accurate estimation of SPAD values in wheat after heading stage can positively impact subsequent nitrogen fertilization management strategies, which regulate grain filling and yield quality formation. In this study, the estimation of SPAD of leaf relative chlorophyll content in spring wheat was conducted at the experimental base in Wuyuan County, Inner Mongolia in 2021. Multispectral images of different nitrogen application levels at 7, 14, 21, and 28 days after the wheat heading stage were acquired by DJI P4M UAV. A total of 26 multispectral vegetation indices were constructed, and the measured SPAD values of wheat on the ground were obtained simultaneously using a handheld chlorophyll meter. Four machine learning algorithms, including deep neural networks (DNN), partial least squares (PLS), random forest (RF), and Adaptive Boosting (Ada) were used to construct SPAD value estimation models at different time from heading growth stages. The model’s progress was evaluated by the coefficient of determination (R2), root mean square error (RMSE), and mean absolute error (MAPE). The results showed that the optimal SPAD value estimation models for different periods of independent reproductive growth stages of wheat were different, with PLS as the optimal estimation model at 7 and 14 days after heading, RF as the optimal estimation model at 21 days after heading, and Ada as the optimal estimation model at 28 d after heading. The highest accuracy was achieved using the PLS model for estimating SPAD values at 14 d after heading (training set R2 = 0.767, RMSE = 3.205, MAPE = 0.060, and R2 = 0.878, RMSE = 2.405, MAPE = 0.045 for the test set). The combined analysis concluded that selecting multiple vegetation indices as input variables of the model at 14 d after heading stage and using the PLS model can significantly improve the accuracy of SPAD value estimation, provides a new technical support for rapid and accurate monitoring of SPAD values in spring wheat.
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Wang, Hongmei, Yue Zhu, Linlin Wang, et al. "Double Mutation of Days to Heading 2 and CONSTANS 3 Improves Agronomic Performance of Japonica Rice under Short Daylight Conditions in Southern China." International Journal of Molecular Sciences 24, no. 8 (2023): 7346. http://dx.doi.org/10.3390/ijms24087346.
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Some progress has been made in understanding the pathways related to rice heading, but their applications to breeding japonica rice varieties adapted to grow in low-latitude areas (“indica to japonica”) are limited. We edited eight adaptation-related genes via a lab-established CRISPR/Cas9 system in a japonica variety, Shennong265 (SN265). All T0 plants and their progeny bearing random mutation permutations were planted in southern China and screened for changes in heading date. We found that the double mutant of Days to heading 2 (DTH2) and CONSTANS 3 (OsCO3) (dth2-osco3), two CONSTANS-like (COL) genes, showed significantly delayed heading under both short-day (SD) and long-day (LD) conditions in Guangzhou and manifested great yield increase under SD conditions. We further demonstrated that the heading-related Hd3a-OsMADS14 pathway was down-regulated in the dth2-osco3 mutant lines. The editing of the COL genes DTH2 and OsCO3 greatly improves the agronomic performance of japonica rice in Southern China.
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Khan, AA, MA Alam, MK Alam, MJ Alam, and ZI Sarker. "Genotypic And Phenotypic Correlation And Path Analysis In Durum Wheat (Triticum turgidum L. var. durum)." Bangladesh Journal of Agricultural Research 38, no. 2 (2013): 219–25. http://dx.doi.org/10.3329/bjar.v38i2.15885.
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An experiment was conducted at Regional Agricultural Research Station, Ishurdi during the 2009-10 cropping season with the objective of estimating the associations between yield and yield-related traits and to identify direct and indirect effects of characters on grain yield in durum wheat. The result showed significant variation among the genotypes for all the characters studied. Significant positive correlation was found for plant height, number of spikes/m2 and 1000-grain weight with grain yield. Heading days and maturity days showed negative correlation with grain yield. Maturity days, number of spikes/m2 and 1000-grain weight had significant positive direct effects on grain yield. Number of grains/spike had also direct positive effect, but in low magnitude. The indirect effect of heading days and plant height on grain yield was found mainly through maturity days and 1000-grain weight. It can be concluded that emphasis should be given on heading days and plant height along with 1000-grain weight, number of spikes/m2 and number of grains/spike for selection of durum wheat genotypes. Bangladesh J. Agril. Res. 38(2): 219-225, June 2013 DOI: http://dx.doi.org/10.3329/bjar.v38i2.15885
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Wang, Jian, Yuexuan Cao, Kejian Wang, and Chaolei Liu. "Development of Multiple-Heading-Date mtl Haploid Inducer Lines in Rice." Agriculture 12, no. 6 (2022): 806. http://dx.doi.org/10.3390/agriculture12060806.
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In vivo doubled haploid (DH) production based on crossing heterozygous germplasm with mtl haploid inducer lines promises to transform modern rice (Oryza sativa) breeding. However, this technology is limited, as haploid inducers and pollen acceptors have asynchronous heading dates. To address this obstacle, we developed a panel of multiple-heading-date mtl haploid inducer lines that produce pollen for more than 35 days. We edited the MTL gene in a hybrid rice with the CRISPR-Cas9 system. We then selected transgene-free homozygous mutants in the T1 generation and reproduced to T4 generation by single-seed descent method. We obtained 547 mtl haploid inducers with diverse heading dates (from 73 to 110 days) and selected 16 lines comprising a core population with continuous flowering. The seed-setting rate and haploid induction rate (HIR) of the core panel were 4.0–12.7% and 2.8–12.0%, respectively. Thus, our strategy of using multiple-heading-date mtl haploid inducers could accelerate the use of in vivo DH technology in rice breeding.
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BARON, V. S., and SOLOMON KIBITE. "RELATIONSHIPS OF MATURITY, HEIGHT AND MORPHOLOGICAL TRAITS WITH WHOLE-PLANT YIELD AND DIGESTIBILITY OF BARLEY CULTIVARS." Canadian Journal of Plant Science 67, no. 4 (1987): 1009–17. http://dx.doi.org/10.4141/cjps87-137.
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Eight six-rowed barley (Hordeum vulgare L.) lines were used to study the relationship of whole-plant dry matter yield (WPY), whole-plant digestible yield (WPDY) and percent in vitro organic matter digestibility (IVDOM) with plant height, maturity, grain and leaf content at the time of maximum WPY. The study was conducted at Lacombe, Alberta during 1983 and 1984. Whole-plant harvests were initiated at the 50% heading stage of individual lines and continued for seven consecutive weeks. WPY and WPDY attained maximum levels at identical harvest times after heading in all lines and years. In 1983 all lines, and in 1984, six of eight lines attained maximum WPY at the same time postheading (fourth and third harvest in 1983 and 1984, respectively). WPY and WPDY were significantly correlated with days from planting to time of maximum yield (TMY) in both years. Partial coefficients of determination from stepwise multiple regression analyses indicated that the effect of days from planting until TMY > plant height > days to heading on WPY. The effect of days from planting until TMY > plant height > IVDOM > days to heading on WPDY, and the effect leaf content was more important than any other variable on IVDOM. It was concluded that late-maturing, tall barley lines having a high leaf content were most likely to produce high WPDY and hence be advantageous for utilization as whole-plant barley forage.Key words: Barley, whole-plant, digestibility, maturity, height
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Tashiro, T., and IF Wardlaw. "The Effect of High Temperature on the Accumulation of Dry Matter, Carbon and Nitrogen in the Kernel of Rice." Functional Plant Biology 18, no. 3 (1991): 259. http://dx.doi.org/10.1071/pp9910259.
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Transferring rice plants (Oryza sativa L. cv. Calrose) growing at 27/22�C to a range of dayhight temperatures 7 days after heading resulted in little variation in kernel size with temperature in the range from 24/19�C (mean 21.7�C) to 30/25�C (mean 26.7�C). This is close to the mean monthly temperature recorded for the rice growing areas of southern Australia during the period of kernel development. There was a significant drop in kernel dry weight with a further increase in temperature to 33/28�C and 39/24�C. When plants were transferred to a temperature of 36/31�C for periods of 8 days, commencing at regular intervals from heading, the greatest change in dry weight of the kernels occurred when the treatment commenced 12 days after heading and the kernels were in the linear phase of dry matter accumulation. The flow of nitrogen into kernels was more stable than that of carbon as temperatures were increased, with little change in nitrogen (mg) per kernel until the temperature was greater than 33/28�C. Changes in temperature away from the optimum (27/22�C) always resulted in an increase in the concentration of kernel nitrogen. The greatest reduction in kernel nitrogen (mg kernel-1), like that of carbon, occurred in high temperature treatments commencing 12 days after heading.
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Ning, Shunzong, Shengke Li, Kai Xu, et al. "Development and Characterization of Near-Isogenic Lines Derived from Synthetic Wheat Revealing the 2 kb Insertion in the PPD-D1 Gene Responsible for Heading Delay and Grain Number Improvement." International Journal of Molecular Sciences 24, no. 13 (2023): 10834. http://dx.doi.org/10.3390/ijms241310834.
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Spikelet number and grain number per spike are two crucial and correlated traits for grain yield in wheat. Photoperiod-1 (Ppd-1) is a key regulator of inflorescence architecture and spikelet formation in wheat. In this study, near-isogenic lines derived from the cross of a synthetic hexaploid wheat and commercial cultivars generated by double top-cross and two-phase selection were evaluated for the number of days to heading and other agronomic traits. The results showed that heading time segregation was conferred by a single incomplete dominant gene PPD-D1, and the 2 kb insertion in the promoter region was responsible for the delay in heading. Meanwhile, slightly delayed heading plants and later heading plants obviously have advantages in grain number and spikelet number of the main spike compared with early heading plants. Utilization of PPD-D1 photoperiod sensitivity phenotype as a potential means to increase wheat yield potential.
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Tiwari, Dev Nidhi, Santosh Raj Tripathi, Mahendra Prasad Tripathi, Narayan Khatri, and Bishwas Raj Bastola. "Genetic Variability and Correlation Coefficients of Major Traits in Early Maturing Rice under Rainfed Lowland Environments of Nepal." Advances in Agriculture 2019 (January 30, 2019): 1–9. http://dx.doi.org/10.1155/2019/5975901.
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Genetic variability is the fundamental requirement of any crop breeding program to develop superior cultivars. The objective of this study was to estimate the genetic variability and find out the correlation among the different quantitative traits of rainfed early lowland rice. The experiment was conducted consecutively two years during 2015 and 2016 in wet season across the four different locations in Regional Agricultural Research Station, Khajura, National Wheat Research Program, Bhairahawa, National Maize Research Program, Rampur, and National Rice Research Program, Hardinath, along the Terai region of Nepal representing subtropical agroclimate. Seven genotypes including Hardinath-1 as standard check variety were evaluated in the randomized complete block design with three replications. Various quantitative traits were measured to investigate the variability and correlation coefficients. All the genotypes and locations showed significant variations for all the traits considered. Genotypic coefficient of variation was lower than phenotypic coefficient of variation for all traits studied. The magnitudes of genotypic coefficient of variations were relatively higher for grain yield, 1000-grain weight, and days to heading. The highest broad sense heritability of 94% was recorded in days to maturity and the lowest heritability of 16% was observed in plant height. Positive and highly significant correlations were found both in genotypic and phenotypic levels between days to heading and days to maturity (rg=0.9999 ⁎⁎, rp=0.997 ⁎⁎), days to heading and grain yield (rg =0.9999 ⁎⁎, rp= 0.9276 ⁎⁎), and days to maturity and grain yield (rg =0.9796 ⁎⁎, rp=0.9174 ⁎⁎). However, negative and highly significant genetic correlation was observed between plant height and 1000-grain weight (rg = -0.9999 ⁎⁎). Thus results indicated that days to heading, days to maturity, grain yield, 1000-grain weight demonstrating higher heritability and remarkable genetic advance could be considered the most appropriate traits for improvement and selection of trait to achieve stable and high yielding early rice genotypes under rainfed environments.
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Zhao, Yijing, Xiaoli Wang, Yu Guo, Xiyong Hou, and Lijie Dong. "Winter Wheat Phenology Variation and Its Response to Climate Change in Shandong Province, China." Remote Sensing 14, no. 18 (2022): 4482. http://dx.doi.org/10.3390/rs14184482.
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Crop phenology is considered to be an important indicator reflecting the biophysical and physiological processes of crops facing climate change. Therefore, quantifying crop phenology change and its relationship with climate variables is of great significance for developing agricultural management and adaptation strategies to cope with global warming. Based on the Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) product, winter wheat green-up date, heading date, jointing date, and maturity date were first retrieved by Savitzky–Golay (S-G) filtering and threshold methods and then the variation of winter wheat phenology and its correlation with mean (Tmean), minimum (Tmin), and maximum (Tmax) temperature and precipitation (Pre) during 2003–2019 were comprehensively analyzed in Shandong Province, China. Results showed that green-up date, jointing date, heading date, and maturity date generally ranged from 50–70 DOY, 75–95 DOY, 100–120 DOY, and 130–150 DOY. Winter wheat phenology presented a spatial pattern of the South earlier than the North and the inland earlier than the coastal regions. For every 1° increase in latitude/longitude, green-up date, jointing date, heading date, and maturity date were respectively delayed by 3.93 days/0.43 days, 2.31 days/1.19 days, 2.80 days/1.14 days, and 2.12 days/1.09 days. Green-up date and jointing date were both advanced in the West and delayed in the Eastern coastal areas and the South, and heading date and maturity date respectively showed a widespread advance and a delayed tendency in Shandong Province, however, the trend of winter wheat phenological changes was generally insignificant. In addition, green-up date, jointing date, and heading date generally presented a significant negative correlation with mean/minimum temperature, while maturity date was positively associated with the current month maximum temperature, notably in the West of Shandong Province. Regarding precipitation, a generally insignificant relationship with winter wheat phenology was detected. Results in this study are anticipated to provide insight into the impact of climate change on winter wheat phenology and to supply reference for the agricultural production and field management of winter wheat in Shandong Province, China.
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Cheng, Mingyuan, Mingchu Zhang, Robert M. Van Veldhuizen, and Charles W. Knight. "Impact of Heading Shift of Barley Cultivars on the Weather Patterns around Heading and Yield in Alaska." Atmosphere 13, no. 2 (2022): 310. http://dx.doi.org/10.3390/atmos13020310.
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Barley heading date has advanced in Fairbanks (64.83° N, 147.77° W), Alaska, USA. However, it is unclear if this advance coincidently causes weather pattern changes around heading and leads to yield loss. Using the Variety Trial and weather data in Fairbanks and Delta Junction (64.05° N, 145.60° W) from 1991 to 2018, two barley cultivars were selected to analyze the yield and weather trends, the yield variation explained by weather, and the effect of extreme weather on yield. The results showed that the heading date of ‘Otal’ significantly advanced and yield significantly declined in Fairbanks while there were no heading and yield changes of ‘Otal’ in Delta Junction and of ‘Thual’ in both Fairbanks and Delta Junction. The weather pattern changed around heading due to advanced heading of ‘Otal’ in Fairbanks. The climate factors at 7–10 days around heading explained over 50% of ‘Otal’ yield variation in Fairbanks. The results suggest that ‘Otal’ can still be good to plant in Delta Junction but not in Fairbanks. To cope with the climate change in Alaska, the farmers should increase the diversity of barley cultivars, select non-photoperiod sensitive cultivars and cultivars with longer duration from planting to heading, and sow late to avoid the impact on heading and yield.
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Yun, Yeotae, Gyucheol Kim, Giwon Cho, and Tugsang Yun. "Effect of Transplanting Date on Agronomic and Grain Quality Traits Using Early-Maturing Rice Varieties." Agronomy 13, no. 5 (2023): 1195. http://dx.doi.org/10.3390/agronomy13051195.
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This study aimed to investigate how transplanting date affects the agronomic and grain quality traits of two early-maturing rice varieties. The experiment was conducted in the rice research field of Chungnam Agricultural Research and Extension Services in South Korea and rice materials were transplanted at intervals of approximately 15 days from 16 April to 16 July in 2019 and 2020. Results showed that agronomic and grain quality traits varied according to the transplanting date and earlier transplanting resulted in a longer period of days from transplanting to heading (DTH). The spikelet number m−2 was highly correlated with the milled rice yield (r = 0.963 ** for Jinbuol, r = 0.909 ** for Yeoreumi) and it significantly decreased as the transplanting date was delayed, which was leading to lower yield. The mean temperature during the grain filling stage had a negative correlation with head rice rate (r2 = 0.825 ** for Jinbuol, r2 = 0.803 ** for Yeoreumi) and the number of days from transplanting to heading showed negative correlation with protein content (r2 = 0.777 ** for Jinbuol, r2 = 0.833 ** for Yeoreumi). Therefore, increasing the number of days from transplanting to heading date can lead to higher milled rice yield and lower protein content and avoiding heading dates on 17 July can improve the appearance traits. As a result, it is suggested that early transplanting is advantageous to increase the milled rice yield and grain quality of early-maturing rice.
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Nasrallah, Ali, Nicolas Baghdadi, Mohammad El Hajj, et al. "Sentinel-1 Data for Winter Wheat Phenology Monitoring and Mapping." Remote Sensing 11, no. 19 (2019): 2228. http://dx.doi.org/10.3390/rs11192228.
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The ability of Synthetic Aperture Radar (SAR) Sentinel-1 data to detect the main wheat phenological phases was investigated in the Bekaa plain of Lebanon. Accordingly, the temporal variation of Sentinel-1 (S1) signal was analyzed as a function of the phenological phases’ dates observed in situ (germination; heading and soft dough), and harvesting. Results showed that S1 data, unlike the Normalized Difference Vegetation Index (NDVI) data, were able to estimate the dates of theses phenological phases due to significant variations in S1 temporal series at the dates of germination, heading, soft dough, and harvesting. Particularly, the ratio VV/VH at low incidence angle (32–34°) was able to detect the germination and harvesting dates. VV polarization at low incidence angle (32–34°) was able to detect the heading phase, while VH polarization at high incidence angle (43–45°) was better than that at low incidence angle (32–34°), in detecting the soft dough phase. An automated approach for main wheat phenological phases’ determination was then developed on the western part of the Bekaa plain. This approach modelled the S1 SAR temporal series by smoothing and fitting the temporal series with Gaussian functions (up to three Gaussians) allowing thus to automatically detect the main wheat phenological phases from the sum of these Gaussians. To test its robustness, the automated method was applied on the northern part of the Bekaa plain, in which winter wheat is harvested usually earlier because of the different weather conditions. The Root Mean Square Error (RMSE) of the estimation of the phenological phases’ dates was 2.9 days for germination, 5.5 days for heading, 5.1 days soft dough, 3.0 days for West Bekaa’s harvesting, and 4.5 days for North Bekaa’s harvesting. In addition, a slight underestimation was observed for germination and heading of West Bekaa (−0.2 and −1.1 days, respectively) while an overestimation was observed for soft dough of West Bekaa and harvesting for both West and North Bekaa (3.1, 0.6, and 3.6 days, respectively). These results are encouraging, and thus prove that S1 data are powerful as a tool for crop monitoring, to serve enhanced crop management and production handling.
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Kim, Yurim, Myoung-Goo Choi, Myoung Hui Lee, et al. "Genome-wide association study to identify the genomic loci associated with wheat heading date variation under autumn-sowing conditions." PLOS One 20, no. 4 (2025): e0322306. https://doi.org/10.1371/journal.pone.0322306.
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The present study aimed to identify genetic loci associated with days to heading (DTH) in wheat under autumn-sowing conditions in Korea, where early heading is critical owing to the overlap between the wheat harvest and the rainy season. We evaluated 530 wheat core collections over five years, focusing on known heading date genes VRN-1 and PPD-1, and conducted a genome-wide association study (GWAS) to identify new genetic loci related to DTH. The results revealed that Korean accessions exhibited the earliest DTH, with modern Korean varieties heading even earlier, reflecting a strong breeding focus on early heading. Among the existing heading date genes, VRN-1 and PPD-D1 were significantly associated with DTH in the wheat core collection. However, all Korean varieties carried the same alleles for each of VRN-A1, PPD-A1, and PPD-D1, resulting in low genetic diversity, which rendered the existing heading date genes insufficient to fully account for the variation in DTH within the Korean varieties. GWAS identified nine single nucleotide polymorphisms (SNPs) associated with DTH in Group A (entire collection filtered, n=518) and six in Group B (accessions with genotypes identical to Korean varieties filtered, n=231). Four key SNPs (AX-95222044 and AX-94685526 in Group A, and AX-94550996 and AX-94970315 in Group B) were selected based on their effect sizes on DTH. In both groups, accessions with alleles for early heading at both of the selected SNPs exhibited the earliest DTH, advancing by 7.7 to 8.9 days. These findings suggest that the selected SNPs, particularly those reflecting the genotypes of Korean varieties, effectively explain the variations in DTH among Korean varieties and could enhance wheat breeding efficiency in Korea. Further research is needed to validate the four selected SNPs and identify the underlying genes, which could serve as valuable markers for developing early-heading wheat varieties suited to Korean autumn-sowing conditions.
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Shah, Syed Ihsan Ullah, Naushad Ali, Hassan Mujtaba, et al. "Genetic Diversity and Heritability Studies for Yield and Yield Related Attributes in Wheat (Triticum aestivum L.)." Planta Animalia 3, no. 2 (2024): 67–75. https://doi.org/10.71454/pa.003.02.0041.
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Evaluation and identification of superior genotypes for general cultivation is considered as crucial concern for any successful breeding scheme. This field experiment was performed at agriculture research station Baffa Mansehra to check variability among different wheat varieties during 2020. Thirty-six wheat varieties along with 2 check cultivar were sown in randomized complete block design (RCB) in two replications. Data recorded for days to emergence, days to heading, days to maturity, plant height, tillers m-2, length of spike, 1000-grain weight, biological yield plot-1 and grain yield plot-1. Data results showed highly significant variations (p<0.01) for days to emergence, days to heading, days to maturity, tiller m-2, thousand grain weight, grain yield plot-1 and significant for (p<0.05) plant height, spike length and biological yield. Variety Shakkar-2013, Fahim-19 and NIFA Awaz produced maximum grain yield plot-1 (0.900) kg, (0.856) kg and (0.854) kg respectively, whereas the minimum grain yield plot-1 (0.350) kg, (0.360) kg was recorded for Wadaan 2017 and PR-138. High heritability recorded for days to emergence, heading days, days to maturity, thousand grain weight, tillers per m2, biological yield and grain yield while moderate for plant height and length of spike. Based on the present research varieties Shakkar-2013 (0.900kg), Fahim-19 (0.856kg) and NIFA Awaz (0.854kg per plot), appeared as the best performing varieties and could be recommended for commercial cultivation at Hazara region.
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Maw, B. R., C. S. Jones, P. C. D. Newton, and J. H. B. Hatier. "Elevated atmospheric CO2 alters heading date of perennial ryegrass." Proceedings of the New Zealand Grassland Association 76 (January 1, 2014): 217–20. http://dx.doi.org/10.33584/jnzg.2014.76.2947.
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Abstract Carbon dioxide (CO2) levels are increasing globally and affect plant growth and development. Time to flowering, commonly referred to as heading date, has been identified as a key indicator of the quality and nutritional value of ryegrass. Recent research on annual grasses indicates that elevated CO2 levels can delay heading date, however significant data for perennial ryegrass is lacking. We exposed currently available ryegrass cultivars to the CO2 concentration expected in 2050 (500 ppm) and found significant changes in heading date with delays and advances of up to 10 days. Over all the cultivars the breadth of heading date was more than doubled, offering potentially new possibilities for cultivar choice for specific environments and systems. Keywords: Lolium perenne, climate change, plant phenology, phosphorus, nitrogen
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Fatimah, Fatimah, Joko Prasetiyono, Ahmad Dadang, Tasliah Tasliah, and Masumah Masumah. "Field Evaluation Of Conde Progenies With Early Heading Date And Resistance To Bacterial Leaf Blight." ANNALES BOGORIENSES 23, no. 2 (2020): 87. http://dx.doi.org/10.14203/ann.bogor.2019.v23.n2.87-96.
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Heading date is one of key traits in rice adaptation to different environments. Rice with early maturity is very useful for increasing rice production extensively especially in Indonesia. The improvement of rice variety Conde for heading date and resistance to bacterial leaf blight (BLB) was developed through Marker Assisted Backcrossing approach (MAB). Xa7 derived from Conde as recipient parents for resistance to BLB and Hd2 gene derived from Nipponbare as a donor parent for heading date. The aim of this research was to evaluate the performance of heading date and agronomic traits of 85 BC2F4 lines in two field stations, Sukamandi (West Java) and Maros (South Sulawesi). Molecular analysis of Xa7 on chromosome 6 and Hd2 gene on chromosome 7 and agronomic performance was evaluated. Foreground analysis resulted 41% for Xa7 and 66.7% for Hd2 gene in homozygous condition. The majority of lines have similar heading date and yield with Conde and more resistance to bacterial leaf blight (BLB) than Conde. Six lines flowered earlier 5 days than Conde in Sukamandi and three lines flowered earlier 3 days in Maros. Twelve lines with flowered earlier than Conde, resistance to BLB and similar yield with Conde were selected for background analysis resulted 93% genome recovery. These lines would be further evaluated in preliminary yield trail for their stability.
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Santhoshini, A., Nidhi Dubey, Harshal Ashok Avinashe, Raju Thonta, and Rajneesh Kumar. "Inheritance Studies in Segregating Population of Bread Wheat (Triticum aestivum L.)." International Journal of Environment and Climate Change 13, no. 9 (2023): 277–87. http://dx.doi.org/10.9734/ijecc/2023/v13i92230.
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The experimental material of present study comprised of 127 treatments and 4 check varieties in augmented design conducted during rabi season (2022) in research field of Genetics and Plant Breeding, Lovely Professional University, Phagwara, India. Observations were recorded for days to 50% heading, days to maturity, plant height, number of productive tillers per plant, ear length, number of spikelets per ear, ear weight, number of grains per ear, test weight, biological yield per plant, harvest index, chlorophyll content and grain yield per plant. Analysis of variance disclosed that treatments and check varieties are highly significant for all the characters. Phenotypic coefficient of variation noted higher magnitude than genotypic coefficient of variation for all the traits. Heritability combined with genetic advance as percent of mean is noted high for grain yield per plant, biological yield per plant, number of productive tillers per plant, ear weight, harvest index, test weight, ear length, number of spikelets per ear, number of grains per ear and plant height. The correlation coefficient assessed positive and highly significant for biological yield per plant, number of productive tillers per plant, harvest index, ear weight, plant height, test weight and ear length. Grain yield per plant recorded positive significant association with biological yield per plant (0.7816), number of productive tillers per plant (0.7051), harvest index (0.527), ear weight (0.4076), plant height (0.3632), test weight (0.3222), and ear length (0.2439), whereas negatively significantly associated with days to 50% heading (-0.4019) and days to maturity (-0.4019). The findings from path analysis unveiled that the maximum direct effect was noted for biological yield per plant, harvest index, number of spikelets per ear, number of productive tillers per plant, ear weight, days to 50% heading, test weight and days to maturity. Out of thirteen traits, eight traits exhibited direct positive effect on grain yield such as biological yield per plant (0.8282), harvest index (0.6061), number of spikelets per ear (0.107), number of productive tillers per plant (0.0191), ear weight (0.0138), days to 50% heading (0.011), test weight (0.0088), and days to maturity (0.0001).
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Tahir, Zeynu, and Asfaw Azanaw. "Adaptation of Malt Barley (Hordeum Vulgare L.) Varieties in the highlands of North Gondar." ABC Journal of Advanced Research 8, no. 1 (2019): 9–14. http://dx.doi.org/10.18034/abcjar.v8i1.83.
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Study was initiated with the objectives to identify high yielder malt barley varieties. The trial has been conducted during 2014 main season and laid out on randomized complete block design with three replications. Analysis of variance was computed using SAS, 2002. At Dabat, result showed that highly significant difference among the varieties (p < 0.05) for all agronomic traits. At Debark and Wegera the analysis of variance indicated that highly significant to a significant difference among varieties at p < 0.05 for days to heading, days to maturity, plant height, spike length, thousand seed weight and grain yield, and seed per spike. The combined analysis of variance showed that highly significant difference among varieties for days to heading, days to maturity, plant height, spike length, and grain yield. The location also contributed the significant effect for all yield components except biomass and grain yield. The interaction of location by genotype showed the highly significant difference on days to maturity and plant height. The average heading days ranged from 70-81 and the average maturity days were ranged from 127-136. Among the tested varieties, IBON-174/03 and SABINI exhibited highest grain yield. The overall combined analysis indicated that IBON-174/03 and SABINI were high yielder and well adapted at the tested sites. Therefore those varieties are recommended for production in the testes sites, and similar agro-ecologies. 
 
 
 
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Mo, Youngjun, Chang-Min Lee, Hyang-Mi Park, et al. "Hd1 Allele Types and Their Associations with Major Agronomic Traits in Korean Rice Cultivars." Plants 10, no. 11 (2021): 2408. http://dx.doi.org/10.3390/plants10112408.
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Optimizing flowering time in crop plants is critical for maximizing yield and quality under target environments. While there is a wide range of heading date variation in Korean rice cultivars, the underlying gene mechanisms are unclear. Here, we sequenced the protein coding regions of Hd1, the major rice heading date gene, from 293 Korean rice cultivars and investigated the associations between Hd1 allele types and major agronomic traits under four different environments. There were four functional Hd1 and five nonfunctional hd1 alleles distributed among the 293 Korean rice cultivars. The effects of the Hd1 allele types were highly significant for days to heading in all four environments, explaining 51.4–65.8% of the phenotypic variation. On average, cultivars carrying nonfunctional hd1 headed 13.7 days earlier than those carrying functional Hd1. While the Hd1 allele types exhibited highly significant effects on culm length and protein content under all four environments, the differences between cultivars carrying Hd1 and hd1 were minimal. The effects of the Hd1 allele types on amylose content were significant in only one of the four environments. Our results provide useful information for fine-tuning rice heading dates by utilizing different Hd1 alleles in rice breeding programs.
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Poetsch, Erich M., Reinhard Resch, and Bernhard Krautzer. "Variability of yield and forage quality between three heading groups of english ryegrass (Lolium perenne L.) during the first growth / Variabilität von Ertrag und Futterqualität zwischen drei Reifegruppen von Englischem Raygras (Lolium perenne L.) im Verlauf des ersten Aufwuchses." Die Bodenkultur: Journal of Land Management, Food and Environment 67, no. 2 (2016): 69–75. http://dx.doi.org/10.1515/boku-2016-0007.
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SummaryLolium perenne L. (Lp) is one of the most important and valuable forage plants in grasslands and an indispensable component of seed mixtures for meadows, pastures, ley farming, and re-seeding measures. A set of 39 different cultivars of Lp assigned to early, intermediate, and late maturing types were harvested and analyzed in weekly intervals during the first growth at AREC Raumberg-Gumpenstein, Austria. Significant differences between the heading groups were found with a time lag of 6 days for crude protein content and of up to 11 days for digestibility of organic matter and energy concentration. The early heading cultivars significantly differed from the other two groups, which performed comparably and were more resilient in terms of quality aspects for a longer time. Within all three heading groups, a strong variation could be noticed, leading to some unexpected overlapping. Our results indicate that the current assignment of Lp cultivars to the heading groups is imprecise and should be improved by advanced recordings and by analyses during the time of the official variety testing period. This may lead to a more sufficient selection of Lp cultivars for grassland mixtures, and therefore, increase the quality of home-grown forage.
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Romanchenko, A. P., and L. I. Strii. "SEMANTIC AND SYNTAX PARAMETRIZATION OF WEATHER FORECAST HEADINGS." Opera in linguistica ukrainiana, no. 29 (November 9, 2022): 78–88. http://dx.doi.org/10.18524/2414-0627.2022.29.262392.
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The heading as an element of meteorological discourse, implemented in the genre of weather forecast, reflects the specifics, which is based on several principles of information coverage. It is a combination of features of scientific, journalistic and artistic styles. The purpose of the research is the lexical and syntactic specificity of headings on Facebook. The object of the research is media heading and the subject of the research – its features in semantical and grammatical aspects. In the process of studying the weather forecasts headings following methods were used: descriptive method (to characterize meteolexemes), component analysis (to specify the semantics of the basic elements of the studied units) and quantitative calculations (to determine the frequency of meteolexemes and structures). The source base for the article was the headings of weather forecasts, represented on the Facebook page of the head of the Cherkasy Regional Center for Hydrometeorology V. Postryhan. The actual base is 300 of these units, recorded in the forecasts-reports from August 12, 2019 to January 31, 2022. The semantic specificity of headings is largely determined by the qualitative and quantitative parameters of used lexemes. The system of words to denote time is the most extensive. Within its limits the most frequent lexemes are singled out: names of seasons, months and days. Those that indicate the temperature parameters of the weather, precipitation and phenomena that specify the course of the weather in a certain period of time were quite active among the actual meteolexemes. Less active components in the headings are geortonyms that serve as chronomarkers of weather conditions. Weather forecast titles are formed as different types of syntactic constructions. Simple constructions prevail and reflect the main content. Complex sentences reflect the main idea of the forecast with certain details and are relatively rarely used. The prospects of the research lie within the lexical and stylistic parameterization of weather forecast headings.
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Cane, Karen, H. A. Eagles, D. A. Laurie, et al. "Ppd-B1 and Ppd-D1 and their effects in southern Australian wheat." Crop and Pasture Science 64, no. 2 (2013): 100. http://dx.doi.org/10.1071/cp13086.
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Photoperiod and vernalisation genes are important for the adaptation of wheat to variable environments. Previously, using diagnostic markers and a large, unbalanced dataset from southern Australia, we estimated the effects on days to heading of frequent alleles of Vrn-A1, Vrn-B1, and Vrn-D1, and also two allelic classes of Ppd-D1. These genes accounted for ~45% of the genotypic variance for that trait. We now extend these analyses to further alleles of Ppd-D1, and four alleles of Ppd-B1 associated with copy number. Variation in copy number of Ppd-B1 occurred in our population, with one to four linked copies present. Additionally, in rare instances, the Ppd-B1 gene was absent (a null allele). The one-copy allele, which we labelled Ppd-B1b, and the three-copy allele, which we labelled Ppd-B1a, occurred through a century of wheat breeding, and are still frequent. With several distinct progenitors, the one-copy allele might not be homogenous. The two-copy allele, which we labelled Ppd-B1d, was generally introduced from WW15 (syn. Anza), and the four-copy allele, which we labelled Ppd-B1c, came from Chinese Spring. In paired comparisons, Ppd-B1a and Ppd-B1c reduced days to heading, but Ppd-B1d increased days to heading. Ppd-D1a, with a promoter deletion, Ppd-D1d, with a deletion in Exon 7, and Ppd-D1b, the intact allele, were frequent in modern Australian germplasm. Differences between Ppd-D1a and Ppd-D1d for days to heading under our field conditions depended on alleles of the vernalisation genes, confirming our previous report of large epistatic interactions between these classes of genes. The Ppd-D1b allele conferred a photoperiod response that might be useful for developing cultivars with closer to optimal heading dates from variable sowing dates. Inclusion of Ppd-B1 genotypes, and more precise resolution of Ppd-D1, increased the proportion of the genotypic variance attributed to these vernalisation and photoperiod genes to ~53%.
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Gan, Y. T., J. G. McLeod, G. J. Scoles, and G. L. Campbell. "Extract viscosity of winter rye: Variation with temperature and precipitation." Canadian Journal of Plant Science 77, no. 4 (1997): 555–60. http://dx.doi.org/10.4141/p96-129.
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Winter rye (Secale cereale L.) is well adapted to the Canadian prairies and rye grain with low extract viscosity (EV) may become an important component in animal diets. Information on how environmental factors affect EV is needed for facilitating the selection of low EV materials and production of low EV grain. Eleven winter rye genotypes were grown in thirteen environments on the Canadian prairies. The grain was studied to determine the effects of precipitation and growing degree-days on EV. The amount of precipitation that plants received 5 wk immediately after heading (P5wk) was closely associated with EV (r = −0.62 to −0.76). Growing degree-days accumulated in 5 wk after heading (GDD5wk) had a smaller but significant (P < 0.05) association to EV (r = 0.34 to 0.61). EV was not correlated with temperature or precipitation during the periods from planting to heading or the whole growing season. For all genotypes tested, EV decreased rapidly with increase of P5wk when P5wk was below 140 mm. When P5wk was greater than 140 mm, the response of EV to P5wk was reduced. Genotypes were significantly different in the response of EV to P5wk; the rate of change in EV with P5wk was greater for some genotypes than for others as indicated by regression slopes. For example, the genotype RT-150 had a regression slope five times greater than that of the genotype G-66S. Our study indicates that the critical growth stage when EV can be affected was after plant heading and that the amount of precipitation that plants receive during the period of 5 wk after heading can be used to predict the relative viscosity level for rye grown in different environments. Key words: Secale cereale, extract viscosity, pentosans, rainfall, degree-days, regression
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Öztürk, İ. "Association between physiological parameters and yield in Triticum aestivum L. genotypes under rainfed conditions." Agricultural Science and Technology 12, no. 2 (2020): 107–13. http://dx.doi.org/10.15547/ast.2020.02.018.
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Abstract. The purpose of the study was to assess the relationships between physiological parameters and grain yield of different bread wheat genotypes. In the present research a total of 25 bread wheat genotypes were tested during the 2016-2017 seasons under rainfed conditions. The experiment was conducted in a randomized complete blocks design with four replications. Grain yield, days of heading, plant height, biomass (NDVI) from GS25 up to GS85 growth stage, chlorophyll content (SPAD) during the heading stage, canopy temperature (CT) at GS60 and GS75 growth stages, and glaucousness were investigated. The results of variance analyses showed that there were significant differences (p<0.01) among genotypes for yield. The mean grain yield was 7948 kg ha-1 and yield ranged from 7033 kg ha-1 to 8759 kg ha-1, the highest grain yield performed by TE6744-16 line. According to the results, significant differences among cultivars in terms of plant height, days of heading, biomass, chlorophyll content, canopy temperature, glaucousness were found. TE6627-6 line had the highest chlorophyll content and also, chlorophyll content positively affected grain yield. Canopy temperature is generally related to yield under drought stress condition in bread wheat. In the study early maturing (days of heading) genotypes had lower canopy temperature. An increase in biomass after the heading phase has positively affected grain yield. In the study, no correlation was found between grain yield and biomass at GS25 and GS45 growth phase. There was a negative correlation between glaucousness with biomass at GS60, GS75 and GS85 growth phase. These results showed that physiological parameters such as biomass (at GS75 and GS85), canopy temperature (at GS60 and GS75), and chlorophyll content (at GS60), and glaucousness could be used for selection parameters under rainfed conditions for yield in bread wheat.
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Murray, GM, RH Martin, and BR Cullis. "Relationship of the severity of Septoria tritici blotch of wheat to sowing time, rainfall at heading and average susceptibility of wheat cultivars in the area." Australian Journal of Agricultural Research 41, no. 2 (1990): 307. http://dx.doi.org/10.1071/ar9900307.
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The severity of epidemics of Septoria tritici blotch (STB) in wheat, caused by Mycosphaerella graminicola, was recorded for a 38-year period at Temora in southern New South Wales. The disease was rated as severe in 11 years, moderate in 11 and nil to light in 15, while very wet conditions prevented sowing in one year. The correlation of disease severity (S, where 0 =nil, 7 =very severe) with environmental and management factors was examined: the correlation was positive with days from sowing to heading and with rainfall ( R-4W , R+4W, mm) and the number of rainy days in the 4-week periods before and after heading; negative with the time of sowing (DS, day of year) and with mean daily maximum temperature in the 4-week periods before and after heading. Days from sowing to heading were negatively correlated with sowing day, and rainy days and mean daily maximum temperature were correlated with total rainfall in the same time period. Addition of these terms did not significantly improve the prediction of severity. The cumulative sum of the recursive residuals from this regression showed a trend with time that was associated with the average susceptibility (SAV, where 1 =highly resistant, 7 =extremely susceptible) of wheat cultivars to STB grown in the district in the previous year. The second model showed that the reduction of the average susceptibility of cultivars grown in an area will reduce the severity of STB. It provided justification for minimum disease standards for cultivars to be grown where STB is potentially severe. Further, it explained the distribution of severity of STB in New South Wales.
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Oosthuyse, S. A., G. Jacobs, and D. K. Strydom. "Growth Response of One-year-old `Granny Smith' Apple Branches in Relation to Time of Heading." HortScience 27, no. 7 (1992): 781–83. http://dx.doi.org/10.21273/hortsci.27.7.781.
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Upright l-year-old apple (Malus domestica Borkh. `Granny Smith') branches were headed at 14-day intervals (branches headed once each) during late winter and in spring [70 days before full-bloom (DBFB) until 28 days after full-bloom (DAFB)] and budbreak and new shoot growth quantified on the remaining branch section after cessation of these events. When heading was performed 70, 56, or 42 DBFB, four to five buds broke on average. When branches were headed subsequently, the average number of buds breaking increased progressively, then decreased with heading date, the maximum number breaking (13) on branches headed 14 DAFB. An average of 10 or 11 buds broke per branch section when heading was performed 28 DAFB. In late summer, the total length of new shoots per branch section for the branches headed before full bloom averaged 113 cm, whereas that on the branches headed at or after full-bloom averaged 76 cm.
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Khanam, Aliya Adiba, Md Shahidur Rashid Bhuiyan, Md Sarowar Hossain, et al. "Characterization of Advanced Lines of Aus Rice (Oryza sativa) Based on Qualitative Traits." PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY 24, no. 5-6 (2023): 28–39. http://dx.doi.org/10.56557/pcbmb/2023/v24i5-68375.
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The present study was conducted at the experimental farm, Department of Genetics and Plant Breeding, Sher-e-Bangla Agricultural University, Dhaka during Aus season, 2017. The experiment was carried out to characterize ten advanced Aus lines (F8) based on qualitative traits. The lines were evaluated in RCBD with three replications. Thirty one qualitative traits were used to characterize the advanced lines. Variation was observed in the traits like leaf pubescence, shape of the ligule, attitude of the blade of flag leaf, days to heading, days to maturity, 1000-grain weight, grain length (without dehulling), sterile lemma length, decorticated grain length (after dehulling), decorticated grain shape, culm length, panicle length. Minimum days to heading was found in L1, L2, L3, L4, L5, and L10. Early maturity was found in L1, L2, L3, L4, L5, and L10. 1000 grain wt. was highest in L2, L4, L6, L7, and L8. Six lines (L1, L2, L3, L4, L5, and L10) showed early time of heading, early maturing and medium type of culm length. Two lines (L7, L9) were observed having long panicle (26-30 cm). It was concluded that the lines L10, L5, L3 and L4 can be selected for further study.
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SATO, Yo-Ichiro. "Effects of days to heading on culm length of rice plants." Ikushugaku zasshi 37, no. 1 (1987): 88–97. http://dx.doi.org/10.1270/jsbbs1951.37.88.
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Vitrakoti, Deepak, Sheetal Aryal, Santosh Rasaily, Bishnu Raj Ojha, Raju Kharel, and Manoj Sapkota. "Study on Genotypic Response and Correlation Analysis of the Yield and Yield Attributing Traits of Different Barley (Hordeum Vulgare) Genotypes." International Journal of Applied Sciences and Biotechnology 4, no. 4 (2017): 529–36. http://dx.doi.org/10.3126/ijasbt.v4i4.16269.
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Barley, being a tremendous opportunities crop, we are far back regarding study, research and utilization. An experiment was conducted 2014-2015 to evaluate the barley genotypes for their yield attributing traits and correlation and causation. Eleven yield contributing traits viz., days to booting, heading and flowering; peduncle length, spike length, plant height, flag leaf area, flag leaf-1 area, thousand grain weight, biological weight and yield per hectare were recorded. High significant variation among genotypes was found for traits under study. Genotypes SBYT3-13#1115 (1960 kg), 14-SB-NAK-MR#17 (1760 kg) and AM POP#26 (1660 kg) were found to be superior for their per se performance based on grain yield per hectare, yield attributing and other quantitative traits. Thousand grains weight (0.333) had positively highest significant correlation with grain yield per hectare followed by spike length (0.310). Grain yield per hectare showed negative highly significant correlation with days to flowering (-0.796) followed by days to heading (-0.761) and days to booting (-0.663). Peduncle length (0.229), plant height (0.226), biological weight (0.181) and flag leaf area (0.032) were positively correlated with grain yield per hectare while flag leaf-1 area(-0.029) was negatively correlated. Thus, selection for genotypes with higher thousand grain weight and spike length accommodating earlier days to flowering, heading and booting is a prerequisite for attaining improvement in grain yield per hectare.Int J Appl Sci Biotechnol, Vol 4(4): 529-536
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Harshwardhan, Harshwardhan, Anil Kumar, Amarjeet Kumar, and Birendra Prasad. "Study of variance, heritability and genetic advance for various yield contributing and quality traits in spring wheat (Triticum aestivum L.)." Journal of Applied and Natural Science 8, no. 4 (2016): 1811–14. http://dx.doi.org/10.31018/jans.v8i4.1045.
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An experiment was conducted to study the coefficient of variance, heritability and genetic advance for different traits in spring wheat .The investigation comprised of 7 lines of wheat and their 21 crosses in half diallel fashion was carried out in RBD with three replications. Data were recorded for days to 75% heading, days to maturity,plant height, number of productive tillers per plant, spike length, number of spikelets per spike, number of grains per spike, grain weight per spike, 1000-grain weight, biological yield per plant, harvest index, grain yield per plant, protein content and sedimentation value. The mean squares of the analysis of variance revealed significant and highly significant differences among genotypes for characters studied. Both PCV and GCV (21.8% and 21.3%) were highest for biological yield per plant followed by grain yield per plant (20.9%) and harvest index (19.7%) respectively. Whereas, ECV was maximum (15.2%) for grain yield per plant followed by harvest index (12.2%) and lowest value was recorded for days to 75% heading (0.85%). Days to 75% heading was highly heritable (90.94%) trait followed by plant height (87.23%) while least heritability (17.73%) was noticed for number of grain per spike. The highest genetic advance shown by the biological yield per plant (48.33g) followed by grain yield per plant (19.75g), however, the greatest genetic value percent mean 43.084 for the days to maturity and minimum (2.10) for spike length. Hence, these statistical parameters might be given top priority to strengthen the successful breeding program.
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Olumekun, Victor O., Abiola T. Ajayi, Tomiloba F. Ojo, Hassana T. Isa, and Vincent A. Lawal. "Drought tolerance assessment and trait associations in two wheat accessions under varying water stress conditions." International Journal of Advanced Natural Sciences and Engineering Researches 7, no. 6 (2023): 113–22. http://dx.doi.org/10.59287/ijanser.1144.
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This study aimed to assess drought tolerance in two wheat accessions (ATTILA-7 and RYENA 28) under different water stress conditions and examine trait associations. The accessions were subjected to well-watered, moderately watered, and drought-stressed treatments. Various yield and yield-determining traits were measured, including plant height, number of tillers, days to heading, spikelets per spike, seeds per plant, and grain yield. Significant differences were observed among accessions and treatments for most traits. RYENA-28 (AC2) performed better under drought stress. Correlation analysis revealed consistent negative correlations between the number of days to heading and the number of seeds per plant across treatments (-0.93, -0.89, and -0.93), while the number of seeds per plant consistently showed significantly positive correlations with grain yield per plant (0.96, 0.97, and 0.82) across treatments. Plant height exhibited negative correlations with the number of tillers and days to heading but positive correlations with grain yield. Notably, the number of spikelets per spike consistently correlated positively with the number of seeds per plant across treatments. These findings provide insights for breeding programs focused on drought tolerance in wheat, emphasizing the selection of accessions with shorter stature, increased spikelets, and higher seed production to develop drought-tolerant wheat varieties with improved yield potential.
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Abiola, Toyin Ajayi, O. Olumekun Victor, T. Isa Hassana, A. Lawal Vincent, and F. Ojo Tomiloba. "Drought tolerance assessment and trait associations in two wheat accessions under varying water stress conditions." International Journal of Advanced Natural Sciences and Engineering 7, no. 6 (2023): 113–25. https://doi.org/10.5281/zenodo.8191467.
Full textAbstract:
This study aimed to assess drought tolerance in two wheat accessions (ATTILA-7 and RYENA-28) under different water stress conditions and examine trait associations. The accessions were subjected to well-watered, moderately watered, and drought-stressed treatments. Various yield and yield-determining traits were measured, including plant height, number of tillers, days to heading, spikelets per spike, seeds per plant, and grain yield. Significant differences were observed among accessions and treatments for most traits. RYENA-28 (AC2) performed better under drought stress. Correlation analysis revealed consistent negative correlations between the number of days to heading and the number of seeds per plant across treatments (-0.93, -0.89, and -0.93), while the number of seeds per plant consistently showed significantly positive correlations with grain yield per plant (0.96, 0.97, and 0.82) across treatments. Plant height exhibited negative correlations with the number of tillers and days to heading but positive correlations with grain yield. Notably, the number of spikelets per spike consistently correlated positively with the number of seeds per plant across treatments. These findings provide insights for breeding programs focused on drought tolerance in wheat, emphasizing the selection of accessions with shorter stature, increased spikelets, and higher seed production to develop drought-tolerant wheat varieties with improved yield potential
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Tiwari, Dev Nidhi, Madhav Prasad Pandey, Hira Kaji Manandhar, and Tej Narayan Bhusal. "Genetic Variability, Heritability and Correlation of Quantitative Traits in Fine and Aromatic Rice Landraces of Nepal." AGRIVITA Journal of Agricultural Science 47, no. 2 (2025): 224. https://doi.org/10.17503/agrivita.v47i2.4651.
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<p>Landraces are reservoirs of desirable and important traits and sources of variations for crop improvement. We evaluated 150 fine and aromatic rice landraces obtained from various regions of the country. The study employed alpha lattice design with two repetitions. Genetic parameters and association studies were performed on the fourteen quantitative traits. Statistical analysis of quantitative traits from evaluated rice landraces revealed significant (p&lt; 0.05) differences for all the traits except the number of unfilled grains. Heading (18.08 and 18.29), maturity days (13.76 and 13.92), and thousand grain weight (20.26 and 21.74) showed narrow variation in genotypic and phenotypic coefficients. Similarly, heading (0.98 and 36.83), maturity days (0.98 and 28.03), plant height (0.72 and 27.66), and thousand grain weight (0.87 and 38.88) recorded high heritability coupled with high genetic advance as percentage of mean. Flag leaf length (0.34**), width (0.31**), and thousand grain weight (0.39**) had highly significant correlation with grain yield. Besides, days to heading (-0.57**, -0.38**) and maturity (-0.57**, -0.38**), tillers (-0.40**, -0.21) were highly significant but negatively correlated. Balamsari Dhan produced the highest grain yield (6.2 t/ha) followed by Rango (5.35 t/ha). The outstanding genotypes could be utilized as donor parents in the future breeding to enhance genetic gain.</p>
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Isa, A., Garba, A.A., Sabo, M.U., and Fagam, A.S. "EVALUATION OF MORPHOLOGICAL TRAITS OF BARLEY (Hordeum vulgare L.) VARIETIES IN DIFFERENT INTER-ROW SPACINGS AND NITROGEN RATES UNDER IRRIGATION." Nigerian Journal of Agriculture and Agricultural Technology 5, no. 1A (2025): 166–75. https://doi.org/10.59331/njaat.v5i1a.980.
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A field experiment was conducted over two consecutive cropping seasons, 2021/2022 and 2022/2023, at the National Root Crop Research Institute’s station in Vom, located in the Jos South Local Government Area of Plateau State (Longitude 8°53' E, Latitude 9º56' N) at an altitude of 1,217 meters above sea level. The aim of the study was to evaluate how different barley genotypes, inter-row spacing, and nitrogen application rates affect barley production. The experimental setup included three barley genotypes (Traveler, Zhana, and Arupo‘s’), four nitrogen levels (0, 80, 100, and 120 kg N ha-1), and three inter-row spacing configurations (20, 30, and 40 cm), organized in a split-split plot design with three replications. The findings indicated that the control treatment resulted in significantly fewer days to heading, with 49.00 days recorded in the 2021/2022 season and 49.30 days in 2022/2023 at a nitrogen application of 80 kg/ha-1. In contrast, the 120 kg N/ha treatment led to delayed heading in both years. However, both the control and the 120 kg N/ha-1 treatment resulted in significantly earlier flowering days at a 40 cm inter-row spacing during both seasons. The genotype Arupo's achieved the highest grain yields, reaching 1251.0 kg/ha in 2021/22 and 1876.4 kg/ha in 2022/23 at a 20 cm inter-row spacing, with the application of 120 kg N/ha-1. The study found significant interactions among the number of days to heading, flowering, physiological maturity, and grain yield concerning nitrogen levels, row spacing, and variety. In conclusion, the genotype Arupo's was the earliest to reach heading, flowering, and maturity, while also yielding the highest grain production in the 20 cm inter-row spacing with a nitrogen level of 120 kg/ha. It is recommended that farmers utilize the Arupo's genotype with a 20 cm inter-row spacing and 120 kg N/ha for optimal barley production.
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Gebru, Akalu, and Agegnehu Mekonnen. "Evaluation of Yield and Yield-Related Trait on the Performance of Bread Wheat Varieties with their Production Package in Atarimesk and Maibar Watershed Wollo, Ethiopia." Journal of Arable Crops and Marketing 1, no. 1 (2022): 11–15. http://dx.doi.org/10.33687/jacm.003.1.2.4164.
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The trial had been conducted using farmer preference and analysis of variance at two locations in Atarimesk and Maibar (top, middle and downstream) watershed. It was replicated three times in each location per farmers and would provide five improved bread wheat varieties and one local variety totally of six varieties. The plot sizes of each variety were 4m*3m and the planting methods were in raw 125 kg/ ha at farmer planting time. The spacing between rows and plots will be 0.2m and 0.5m respectively. Analysis of variance over the two locations revealed that highly significant difference (0.01) over in days to heading, and grain yield, and Analysis of variance in maibar location days to heading, days to maturity, plant height, thousand seed weight, and grain yields were highly significant. In Atarimesk location days to heading and grain yields were highly significant. But days to mature, spike length, and thousand seed weight were non-significant. Variety. Tsehay and sorra took the short number of days to head and mature, these help to escape drought occurrence in eastern Amhara. As far as disease reaction is concerned, Variety Tsehaye no disease incidence in two locations. But variety sorra shows five percent incidence with less than five percent severity in one farm, only one replication. Farmers were select variety sorra and Tsehay by their own selection criteria. From the analysis of variance, Variety sorra and Tsehay 34 kg/ha and 27 kg/ha give yield advantage over the local variety respectively. Therefore, Variety Sorra and Tsehay are recommended for further production in Maibar, Atarimesk and similar agro-ecologies.
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Khan, Imran, Fida Mohammad, and Fahim Ullah Khan. "Estimation of genetic parameters of yield and yield traits in wheat genotypes under rainfed conditions." International Journal of Environment 4, no. 2 (2015): 193–205. http://dx.doi.org/10.3126/ije.v4i2.12637.
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Development of superior crop varieties is the prime objectives of all plant breeding programs. To determine genetic variability, heritability and genetic advance, 24 elite bread wheat lines were planted in randomized complete block design with three replications at the University of Agriculture, Peshawar under rainfed conditions. Data were recorded on days to heading, days to maturity, plant height (cm), flag leaf area (cm-2), spike length (cm), grain yield (kg ha-1), biological yield (kg ha-1), 1000 grain weight (g), grains spike-1, grain weight spike-1(g), and harvest index (%). Analysis of variance revealed significant differences among genotypes for all the traits studied. Broad sense heritability was high for days to heading (0.89), grain weight spike-1(0.61g), spike length (0.70 cm), 1000-grain weight (0.62g), grain yield (0.78 kg ha-1) and harvest index (0.62%); and was moderate for days to maturity (0.52), plant height (0.38 cm), and grains spike-1 (0.49), while low heritability was estimated for spike weight (0.25g), flag leaf area (0.28 cm-2) and biological yield (0.25 kg ha-1). The values of genetic advance for days to heading, days to maturity, plant height, spike length, grains spike-1, grain weight spike-1, 1000-grain weight, grain yield, biological yield, flag leaf area, and harvest index were; 5.47, 1.88, 4.01, 6.42, 0.16, 5.02, 0.71, 418.83, 379.64, 2.89 and 3.92, respectively. Genotype PR 105 surpassed all other genotypes in grain yield (3144.33 kg ha-1) and hence it can be recommended for rainfed area. DOI: http://dx.doi.org/10.3126/ije.v4i2.12637 International Journal of Environment Vol.4(2) 2015: 193-205
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Sharma, Subarna, Nav R. Acharya, Sharad Adhikari, and Krishna K. Mishra. "ANALYSIS FOR YIELD AND YIELD COMPONENTS OF WHEAT GENOTYPES UNDER IRRIGATED CONDITIONS IN MID-WESTERN TERAI OF NEPAL." EPH - International Journal of Agriculture and Environmental Research 1, no. 2 (2017): 60–64. http://dx.doi.org/10.53555/eijaer.v1i2.20.
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With the objective of identifying high yielding wheat varieties for irrigated condition of midwestern region of Nepal, Coordinated Varietal Trials (CVT) of wheat were planted under irrigated conditions at Regional Agriculture Research Station (RARS) Khajura in winter season of 2011/12 and 2012/13. Trials were planted in Randomized Complete Block Design (RCBD) and recommended cultivation practices were followed. Various phenological, morphological and yield attributing traits were recorded. Obtained data of both years were analyzed by using MSTATC software program. Correlation and path analysis for yield was conducted by using SPSS and MS-Excel. Combined analysis over year indicated highly significant differences among the genotypes in terms of days to heading, days to maturity, thousand kernels weight, grain yield and straw yield. The difference was significant for plant height but non-significant in terms of grains per spike. Among the tested entries included in the experiment, NL 1135 had late heading and maturity. In contrast, genotype BL 3978 was earliest. Genotype Gautam was obtained to be tallest and Thousand kernels weight was obtained highest in genotype BL3978. Grain yield was obtained significantly high over the years in NL1094 followed by NL 1135. Maximum straw yield was obtained in genotype NL 1094 followed by NL1135. Correlation coefficient computation showed that days to maturity had highest positive correlation (0.684**) with days to heading. Path analysis for yield revealed that thousand kernels weight had the highest positive value (0.732681) as compared to direct effect of other traits.
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Wang, Hongfei, Aniruddha Ghosh, Bruce A. Linquist, and Robert J. Hijmans. "Satellite-Based Observations Reveal Effects of Weather Variation on Rice Phenology." Remote Sensing 12, no. 9 (2020): 1522. http://dx.doi.org/10.3390/rs12091522.
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Obtaining detailed data on the spatio-temporal variation in crop phenology is critical to increasing our understanding of agro-ecosystem function, such as their response to weather variation and climate change. It is challenging to collect such data over large areas through field observations. The use of satellite remote sensing data has made phenology data collection easier, although the quality and the utility of such data to understand agro-ecosystem function have not been widely studied. Here, we evaluated satellite data-based estimates of rice phenological stages in California, USA by comparing them with survey data and with predictions by a temperature-driven phenology model. We then used the satellite data-based estimates to quantify the crop phenological response to changes in weather. We used time-series of MODIS satellite data and PhenoRice, a rule-based rice phenology detection algorithm, to determine annual planting, heading and harvest dates of paddy rice in California between 2002 and 2017. At the state level, our satellite-based estimates of rice phenology were very similar to the official survey data, particularly for planting and harvest dates (RMSE = 3.8–4.0 days). Satellite based observations were also similar to predictions by the DD10 temperature-driven phenology model. We analyzed how the timing of these phenological stages varied with concurrent temperature and precipitation over this 16-year time period. We found that planting was earlier in warm springs (−1.4 days °C−1 for mean temperature between mid-April and mid-May) and later in wet years (5.3 days 100 mm-1 for total precipitation from March to April). Higher mean temperature during the pre-heading period of the growing season advanced heading by 2.9 days °C−1 and shortened duration from planting to heading by 1.9 days °C−1. The entire growing season was reduced by 3.2 days °C−1 because of the increased temperature during the rice season. Our findings confirm that satellite data can be an effective way to estimate variations in rice phenology and can provide critical information that can be used to improve understanding of agricultural responses to weather variation.
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Mujtaba, Hassan, Wasiq Saeed, Noshin Shafqat, et al. "Evaluating the Bread Wheat Germplasm for Yield and Adult Plant Resistance to Yellow Rust under Field conditions of Mansehra." Journal of Agriculture and Veterinary Science 3, no. 3 (2024): 529–40. https://doi.org/10.55627/agrivet.003.03.1059.
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Yellow rust (Puccinia Striiformis f. sp. tritici) is a major disease that significantly impacts wheat yield and grain quality. Yellow rust poses a serious threat to wheat production in cooler areas of Pakistan. To evaluate the resistance at adult plant stage against yellow rust a set of 47 wheat varieties alongside two checks i-e; Kohat-2000 and Kohat-2017 were planted during 2018–19 cropping season. Data were recorded on days to heading, days to maturity, plant height (cm), flag leaf area (cm2), tillers m-2, spike length (cm), grains spike-1 (no.), 1000-grain weight (g), grain yield (g plot-1) and yellow rust scoring. Significant differences were found between genotypes for days to heading and 1000-grain weight. According to adjusted mean data, Shahkar-2013 had the lowest ideal days to heading (112 days) and days to maturity (157 days), but TD-1's plant height (69 cm) was the highest. Pakistan-2013 had the highest results for flag leaf area (37.3 cm2), tillers m-2 for Frontana (172 m-2), grains spike-1 for Gold-2016 (60 grains), and spike length (12.5 cm), while NIFA-Lalma-2013 had the highest grain weight (70 g) and Pavan had the highest grain yield plot-1 (250 g). Pavan, Frontana, Wadaan-2017, Tatara-96, NIFA Aman, Parula, Fateh Jhang, Pirsabak-2013, Paseena-2017, Khushal-69, Gold-2016, Pirsabak-2005, Ujala, Khaista-2017, Kohat-2017, Pirsabak-2015, and Pakistan-2013 are among 17 genotypes that were found to be high yielding and disease resistant based on yield as well as resistant against yellow rust. These 17 genotypes should be promoted for widespread cultivation in the Mansehra region to enhance wheat productivity and ensure food security while minimizing the impact of yellow rust.
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Singh, Anoj Kumar, Vaidurya Pratap Sahi, Munish Kumar Singh, Sunil Kumar, and Prashant Kumar Rai. "Harnessing Wheat's Genetic Diversity from Heat-Tolerant, High-Yielding Varieties." Journal of Advances in Biology & Biotechnology 28, no. 5 (2025): 752–61. https://doi.org/10.9734/jabb/2025/v28i52336.
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The experimental study included 58 bread wheat genotypes of 45 F1 hybrids, 10 parental lines, and three control varieties. This research was conducted during the Rabi seasons of 2022-23 and 2023-24 at the Field Experimentation Centre within the Department of Genetics and Plant Breeding at SHUATS in Prayagraj, Uttar Pradesh. A randomized block design with three replications was used for the experiment. The parental lines included SHUATS-W8, SHUATS-W10, SHUATS-W12, SHUATS-W13, SHUATS-W16, SHUATS-W21, SHUATS-W66, SHUATS-W67, SHUATS-W86, and SHUATS-W87, which were crossed using a half-diallel cross design. The variance analysis showed significant differences (α=0.05) across all 18 traits in both timely (E1) and late sown (E2) environments, highlighting substantial genetic variability among bread wheat germplasms and indicating strong potential for selection-based improvement. Traits such as plant height, days to first heading, days to 50% flowering, days to maturity, and test weight showed minimal differences between GCV and PCV in both environments, indicating a lower environmental impact and a higher degree of genetic control over their expression. In contrast, traits like the number of grains per spike and chlorophyll content exhibited more significant GCV-PCV differentials, suggesting a greater environmental effect on their phenotypic traits. Notably, high heritability and significant genetic advance as a percentage of the mean were found for test weight, plant height, and days to maturity, emphasizing the influence of additive gene action and making these traits prime candidates for direct selection in breeding initiatives. Traits such as days to first heading and days to 50% flowering showed moderate GCV, high heritability, and moderate genetic advance, indicating a reasonable potential for genetic enhancement. The pooled mean analysis further confirmed that test weight and days to first heading displayed high genetic variability, heritability and genetic advance, positioning them as important targets for wheat improvement efforts.
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Jenni, Sylvie. "Rib Discoloration: A Physiological Disorder Induced by Heat Stress in Crisphead Lettuce." HortScience 40, no. 7 (2005): 2031–35. http://dx.doi.org/10.21273/hortsci.40.7.2031.
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Rib discoloration in crisphead lettuce (Lactuca sativa) has been successfully induced by applying heat stress. Two studies were conducted to determine the effect of short periods (3 and 5 days) of high temperatures (35/25 °C and 35/15 °C day/night temperatures) at various developmental stages (at heading, and at 1, 2, and 3 weeks after heading) on rib discoloration incidence and severity. Lettuce (cv. Ithaca) was most sensitive to heat stress 2 weeks after heading: applying 35/25 °C or 35/15 °C day/night temperatures for 3 or 5 days resulted on average in 46% of mature heads with rib discoloration symptoms. Stressing plants at earlier or later stages resulted in significantly lower incidences of the disorder, with only 4% to 17% plants showing symptoms. More leaves were affected by the disorder when heat stress was applied 2 weeks after heading than when the stress was applied earlier or later. Night temperature and stress duration had no effect on the incidence and severity of rib discoloration. Up to eight leaves, located between the first and fifteenth leaves acropetal to the cap leaf, showed symptoms. This report establishes a direct relationship between rib discoloration and heat stress, proposes a new method to help lettuce breeders screen germplasm for rib discoloration tolerance, and supports the development of tools for predicting the occurrence of rib discoloration in the field according to meteorological data.
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Ali, Iftikhar, Liang Tang, Junjie Dai, et al. "Responses of Grain Yield and Yield Related Parameters to Post-Heading Low-Temperature Stress in Japonica Rice." Plants 10, no. 7 (2021): 1425. http://dx.doi.org/10.3390/plants10071425.
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There is unprecedented increase in low-temperature stress (LTS) during post-heading stages in rice as a consequence of the recent climate changes. Quantifying the effect of LTS on yields is key to unraveling the impact of climatic changes on crop production, and therefore developing corresponding mitigation strategies. The present research was conducted to analyze and quantify the effect of post-heading LTS on rice yields as well as yield and grain filling related parameters. A two-year experiment was conducted during rice growing season of 2018 and 2019 using two Japonica cultivars (Huaidao 5 and Nanjing 46) with different low-temperature sensitivities, at four daily minimum/maximum temperature regimes of 21/27 °C (T1), 17/23 °C (T2), 13/19 °C (T3) and 9/15 °C (T4). These temperature treatments were performed for 3 (D1), 6 (D2) or 9 days (D3), at both flowering and grain filling stages. We found LTS for 3 days had no significant effect on grain yield, even when the daily mean temperature was as low as 12 °C. However, LTS of between 6 and 9 days at flowering but not at filling stage significantly reduced grain yield of both cultivars. Comparatively, Huaidao 5 was more cold tolerant than Nanjing 46. LTS at flowering and grain filling stages significantly reduced both maximum and mean grain filling rates. Moreover, LTS prolonged the grain filling duration of both cultivars. Additionally, there was a strong correlation between yield loss and spikelet fertility, spikelet weight at maturity, grain filling duration as well as mean and maximum grain filling rates under post-heading LTS (p < 0.001). Moreover, the effect of post-heading LTS on rice yield can be well quantified by integrating the canopy temperature (CT) based accumulated cold degree days (ACDDCT) with the response surface model. The findings of this research are useful in modeling rice productivity under LTS and for predicting rice productivity under future climates.