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1
Sun, Jingbin, Xueqiang Li, Shaochuan Li, Xiangyou Wang, and Linlin Wang. "Design Optimization and Experiment of Four-Row Potato Seedling-Cutting Machine." Applied Engineering in Agriculture 37, no. 6 (2021): 1155–67. http://dx.doi.org/10.13031/aea.14532.
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HighlightsBased on the innovative analysis of the seedling-cutting operation mechanism, five shapes of seedling-cutting blades were designed, and a four-row potato seedling-cutting machine was developed.The kinematics and mechanics of seedling-cutting blades were analyzed, which can provide a theoretical basis for the selection of experimental factors.A regression orthogonal experiment and variance analysis were carried out to verify the performance of the four-row potato seedling-cutting machine. Finally, the main and secondary factors affecting the seedling-cutting performance and the optimal parameter combination were obtained.Compared with other studies, the structure of the seedling-cutting blades are more complete in this study. The test results show that the qualified rate of the broken length of the potato seedlings is significantly improved, the missed cutting rate of the potato seedlings is reduced, and the length of the stubble is more uniform, which greatly improves the quality of seedling-cutting.Abstract. A four-row potato seedling-cutting machine was designed to address the problems associated with potato seedling-cutting machines with low qualified rates of broken length and stubble length and high missed cutting rates. Based on the analysis of the seedling-cutting operation mechanism, key components were designed, and the kinematics and mechanics were analyzed. A regression orthogonal experiment was carried out, taking the rotation speed of the seedling-cutting blade shaft, forward speed of the seedling-cutting machine, and height of the short blade of the ridge top from the ridge platform as the experimental factors and the qualified rate of the broken length of the potato seedlings, missed cutting rate of the potato seedlings, rate of carrying potatoes, and length of the stubble as experimental indexes. The results showed that the prioritized impact of various factors on the qualified rate of the broken length of the potato seedlings ranked as follows: the rotation speed of the seedling-cutting blade shaft > the height of the short blade of the ridge top from the ridge platform > the forward speed of the seedling-cutting machine. The prioritized impact of various factors on the missed cutting rate of the potato seedlings ranked as follows: the forward speed of the seedling-cutting machine > the rotation speed of the seedling-cutting blade shaft > the height of the short blade of the ridge top from the ridge platform. The prioritized impact of various factors on the rate of carrying potatoes and the length of the stubble ranked as follows: the height of the short blade of the ridge top from the ridge platform > the rotation speed of the seedling-cutting blade shaft > the forward speed of the seedling-cutting machine. The optimal parameter combination was a rotation speed of the seedling-cutting blade shaft of 1400 r/min, forward speed of the seedling-cutting machine of 4.22 km/h, height of the short blade of the ridge top from the ridge platform of 62 mm. Based on this combination, the qualified rate of the broken length of potato seedlings was 94.1%, the missed cutting rate of the potato seedlings was 0.30%, the rate of carrying potatoes was 0.49%, and the length of the stubble was 54 mm. The index values of the verification experiments were 94.6%, 0.38%, 0.53%, and 56 mm, which were better than the standard values, indicating that this machine meets the basic operation requirements. The test results can provide theoretical support and technical reference for improving the parameter and structural design of a potato seedling-cutting machine. Keywords: Field experiment, Flail blade, Potato, Seedling-cutting machine.
2
Zhou, Biao, Hong Miao, Chunsong Guan, Xin Ji, and Xiaochan Wang. "Design and Test of Seedling-Picking Mechanism of Fully Automatic Transplanting Machine." Applied Sciences 14, no. 20 (2024): 9235. http://dx.doi.org/10.3390/app14209235.
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The seedling retrieval mechanism is a crucial component of fully automatic transplanting machines, significantly influencing the quality, reliability, and efficiency of the transplanting process. Nonetheless, the existing seedling retrieval mechanisms in current transplanting machines exhibit several deficiencies, including substantial damage to seedlings and inadequate retrieval accuracy. To overcome these challenges, we propose an integrated approach combining pneumatic and mechanical techniques to further improve performance. By employing a lower thimble elevation and clamping mechanism, alongside a mathematical model based on the seedling removal process, this method ensures precise seedling extraction and minimizes damage to the root system and substrate. The novelty of this study lies in its ability to reduce the adhesion between seedlings and the holes of the plug plate, thereby minimizing non-destructive extraction of the seedlings and preserving the integrity of the matrix, which is essential for ensuring healthy seedling growth. Moreover, the optimization of the seedling retrieval trajectory enhances the accuracy of the seedling retrieval mechanism while also meeting the requisite speed requirements. Experimental results indicate that at a rate of 72 seedlings per minute, the extraction success rate reached 94.90%, and the casting success rate was 98.53%. The seedling injury rate was only 1.95%, resulting in an overall success rate of 91.69%. These findings confirm that the device meets operational efficiency requirements and delivers effective performance.
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Zheng, Shuhe, Jicheng Li, Zhenfa Dong, et al. "Design and Experiments of Automatic Seedling Separation Device for Vegetable Substrate Block Seedling Transplanter." Agriculture 15, no. 4 (2025): 428. https://doi.org/10.3390/agriculture15040428.
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To address the critical challenges of low success rates and high seedling damage in automatic transplanters for vegetable substrate block seedlings, this study took cabbage substrate block seedlings as the research object and designed a silica gel wheel–synchronous belt clamping seedling separation device. An experimental platform was constructed to perform a three-factor, three-level orthogonal test, investigating the effects of the wheelbase of the silica gel wheel, the inclination angle of the conveyor belt, and the wheelbase of the silica gel wheel and the synchronous belt on seedling separation success rate and substrate block breakage rate. A quadratic regression model was established to analyze the influence of each factor on the index and to optimize the parameter combination verification test. The results showed that the seedling separation effect was better when the wheelbase of the silica gel wheel was 60.47 mm, the inclination angle of the conveyor belt was 8.67°, and the wheelbase of the silica gel wheel and seedling separation synchronous belt was 39.8 mm. The success rate of seedling separation was 90.21% and the substrate block breakage rate was 6.88% in the field verification test of this parameter combination. When the operating speed is 60 plants/min, there is a higher success rate of seedling separation and a lower substrate block breakage rate. This study explored the conditions for stable seedling separation using the seedling separation device, and provided practical reference for the study of the automatic seedling separation of substrate block seedlings.
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Hossen, MA, MM Hossain, ME Haque, and RW Bell. "Effect of Seed Rate on Seedling Quality for Mechanical Rice Transplanting." Bangladesh Rice Journal 22, no. 1 (2019): 9–23. http://dx.doi.org/10.3329/brj.v22i1.41834.
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A study was conducted in the Farm Machinery and Postharvest Technology Division, Bangladesh Rice Research Institute (BRRI), Gazipur in the irrigated dry season (Boro) of 2012-13. It was aimed at identifying the optimum seed rate of different graded rice variety for mat type seedlings preparation and suitable seedling adjustment option of the rice trans planter to maintain required number of seedlings dispensed per stroke by the rotary picker of the trans planter. Walk behind type 4-rows rice trans planter (DP 480) was used to conduct the study. The experiment was followed as two factorial completely randomized design (CRD) with three replications. Three categories of rice variety as short and bold grain (cv. BR3), medium and slender grain (cv. BRRI dhan28) and extra-long and slender grain (cv. BRRI dhan50) were considered as main factor whereas seed rate of 100, 120, 130, 140, 150 and 160g pertray (280×580×25 mm) were considered as sub-factor. Irrespective of rice category, seedling emergence decreased with the increase of seed rate. Seedling emergence decreased from 77 to 56, 74 to 57 and 77 to 54% in BR3, BRRI dhan28 and BRRI dhan29 respectively with the increase of seed rate from 100 to 160g per tray. Seed rate did not affect the seedling height significantly whereas it was varied with the rice verities only and BRRI dhan50 produced higher seedling length. However, number of leaf, stem thickness and shoot dry weight decreased and root-shoot ratio increased significantly with the increase of seed rate. The highest shoot dry weight was observed in BR3 followed by BRRI dhan50. Seedling strength also decreased with the increase of seed rate. The highest seedling strength (0.043 mg cm-1) was observed for the seed rate of 100g of BR3 and the lowest (0.020 mg cm-1) for the seed rate of 160g of BRRI dhan28. The number of seedling increased and percentage of missing hills decreased with the increase of both the seed rate and seedling adjustment option of the rice transplanter irrespective of variety. In case of BR3, seedling dispensed per stroke and percentage of missing hills varied from 4.3 to 5.7 and 6.8 to 7.8 for the seed rates of 140, 150 and 160 g of seeds tray-1 for 5 to 7 seedling adjustment option of the rice transplanter respectively. Seedlings per stroke and percentage of missing hills of BRRI dhan28 for the seed rate of 130, 140 and 150 g of seeds tray-1 was found almost same for 5 to 7 seedling adjustment options of the rice transplanter (4.2 to 6.3 and 5.7 to 9.8). However, there was minimum difference of seedlings per stroke and percentage of missing hills among 120, 130 and 140 g of seeds tray-1 for the option of 4 to 7 (4.0 to 5.6 and 3.9 to 7.8 respectively) for BRRI dhan50. It can be concluded that 140 g of seeds tray-1 for short and bold grain (BR3) and 130 g of seeds tray-1 for medium and slender grain (BRRI dhan28) under the seedling adjustment options of 5 to 7 and 120 g of seeds tray-1 for extra-long and slender grain (BRRI dhan50) under the seedling adjustment options of 4 to 7 may be used for desired seedlings per hill and minimum missing hills along with good quality of seedling.
 Bangladesh Rice j. 2018, 22(1): 9-23
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Peng, Zehui, Fazhan Yang, Yuhuan Li, Xiang Li, Baogang Li, and Guoli Xu. "Design and Testing of a Whole-Row Top-Loosening Stem-Clamping Seedling Extraction Device for Hole Tray Seedlings." Agriculture 15, no. 2 (2025): 165. https://doi.org/10.3390/agriculture15020165.
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A combined seedling extraction device was developed that operates by first top loosening and then clamping the stem in order to solve the current issues with automated transplanting technology, such as low seedling extraction efficiency and a high rate of substrate loss. The pepper plug tray seedlings were selected as the experimental subjects for testing the mechanical properties of the stems. The tensile and compressive mechanical properties of the stems were obtained, and the kinematic model of the seedling spacing process and the mechanical model of the seedling clamping process were established. Key parameters of the seedling extraction device were analyzed and calculated, and an automated seedling extraction system was constructed. Using substrate moisture content, seedling age, and extraction frequency as experimental factors, orthogonal tests were conducted. Through variance analysis and 3D response surface analysis, the optimal rounded parameter values were determined: 48% substrate moisture content, 38-day-old seedlings, and a seedling extraction frequency of 60 plants/min. Under these conditions, the seedling extraction success rate was 94.44%, the substrate loss rate was 6.07%, and the seedling damage rate was 4.17%, meeting the requirements for automated seedling extraction.
6
Yang, Jiajia, Maile Zhou, Daqing Yin, and Jianjun Yin. "Design and Development of Rice Pot-Seedling Transplanting Machinery Based on a Non-Circular Gear Mechanism." Applied Sciences 14, no. 3 (2024): 1027. http://dx.doi.org/10.3390/app14031027.
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Transplanting rice pot seedlings without damaging the roots, which promotes early tillering, is an effective measure to enhance rice yield and quality. This study aimed to obtain the mechanized-transplanting trajectory and attitude of rice pot seedlings by utilizing non-circular planetary-gear trains, focusing on the three key actions of rice pot-seedling transplanting: seedling picking, conveying, and planting. A lightweight and simplified rice pot-seedling transplanting machinery was designed, referring to the motion characteristics of artificially transplanting rice pot seedlings by first pulling them out and then planting them. Key technologies such as non-circular gear trains, the rice seedling supply system, the transmission system, and the rice seedling-picking device were studied, and their key components were designed and manufactured, resulting in the creation of two physical model machines: an ordinary ride type and a high-speed type. The seedling-picking test and field-transplanting test showed that the rice pot-seedling transplanting mechanism can accomplish the rice pot-seedling picking, rice conveying, and planting actions. The designed operation efficiency yielded a planting-depth qualification rate of over 92%, a seedling injury rate of less than 1.2%, and a missed-transplanting rate of less than 2%.
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Zhang, Bingchao, Xiangyu Wen, Yongshuang Wen, et al. "Design and Testing of a Closed Multi-Channel Air-Blowing Seedling Pick-Up Device for an Automatic Vegetable Transplanter." Agriculture 14, no. 10 (2024): 1688. http://dx.doi.org/10.3390/agriculture14101688.
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In this study, a closed multi-channel air-blowing plug seedling pick-up device and a combined plug tray were designed to address the issues of complex structure, high seedling damage rates and low pick-up efficiency in fully automated vegetable transplanter systems. The device operates by sealing the plug seedlings in a seedling cup, where compressed air is channeled into the sealed cavity through multiple passages during the seedling pick-up process. The upper surface of the seedling plug is subjected to uniform force, overcoming the friction and adhesion between the plug seedlings and the tray. This process presses the seedlings into the guide tube, completing the pick-up operation. A mechanical model for the plug seedlings was developed, and the kinetics of the pick-up process were analyzed. The multi-channel high-pressure airflow was simulated and evaluated, identifying three key parameters affecting seedling pick-up performance: water content of the seedling plug, air pressure during pick-up, and air-blowing duration. Using these factors as variables, and with seedling pick-up rate and substrate loss rate as evaluation indicators, single-factor experiments and a three-factor, three-level orthogonal experiment were conducted. The experiments’ results showed that the best seedling pick-up performance was achieved when the water content of the plug was 20%, the air pressure was 0.3 MPa, and the air-blowing time was 30 ms. Under these conditions, the seedling pick-up success rate was 97.22%, and the substrate loss rate was 10.46%.
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Reay, S. D., and P. J. Walsh. "A carbosulfan insecticide to protect pine seedlings from Hylastes ater (Coleoptera Scolytidae) damage." New Zealand Plant Protection 55 (August 1, 2002): 80–84. http://dx.doi.org/10.30843/nzpp.2002.55.3923.
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A controlled release granular carbosulfan pesticide was tested for efficacy against Hylastes ater damage of Pinus radiata seedlings in secondrotation forests in the central North Island Our study involved control seedlings and seedlings treated with 10 g or 15 g carbosulfan granules per seedling Seedling mortality ranged from 0 to 8 at the five sites When seedling mortality was high (8) mortality was reduced to 07 and 0 for carbosulfan granules applied at 10 g/seedling and 15 g/seedling respectively While seedling mortality in the five sites was low a large proportion of seedlings were damaged (38 to 83 of untreated seedlings) by H ater Untreated seedlings were damaged more frequently and with greater severity than treated seedlings The results indicate that that carbosulfan should protect P radiata seedlings from damage caused by H ater when used at the recommended field rate
9
Zhao, Wen Ju, Li Rong Wang, Hong Ji, Jian Shu Song, and Yan Wei Fan. "Impacts of Plant Additive on the Seedling Bricks’ Physical Properties." Advanced Materials Research 518-523 (May 2012): 5401–5. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.5401.
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Homemade seedling bricks, which mixed and suppressed with the plant additive, clay, compost, slow-release fertilizer, can create a good living environment for plant growth, guide the development and growth of plant roots, achieve integration of bricks and seedlings to plant, and the seedlings transplant without time limit. We tested the molding density, shatter resistance, seepage rate and other physical properties of seedling bricks without plant additive, adding 5% and 10% of wheat straw, wheat shells and corn leaves, and the results show that adding plant additive can improve the physical properties of the seedling bricks effectively. The minimum density of the seedling brick contains 10% corn leaves, the minimum shatter resistance of the seedling brick contains 10% wheat straw, and the maximum seepage rate of the seedling brick contains 10% wheat straw.
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KR, Reshmi Raj, Gopala Krishnan S, Arun Kumar MB, and VP Bansal. "Influence of differential root and shoot growth rate on seedling vigour index in rice." Oryza-An International Journal on Rice 59, no. 3 (2022): 323–29. http://dx.doi.org/10.35709/ory.2022.59.3.7.
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Early seedling vigour is an important trait in direct seeded rice which determines the growth and yield. It is a complex trait and is found to be associated with germination and seedling growth. The rice genotypes, BPT 5204 and PB 1850-27 were screened for early seedling vigour traits and the data was recorded on germination percentage, root length, shoot length, seedling length, seedling fresh weight and seedling dry weight. The seedling vigour index I and seedling vigour index II were calculated for both the genotypes. It was observed that seedling vigour index I and II was found higher in PB 1850-27 as compared to BPT 5204. The principal component analysis was done to study differential root and shoot growth rate in F1 plants with parents. It was observed that growth rate in F1 seedlings was found higher than both the parents. The root growth in F1 plants resemble BPT 5204 during initial days of germination, while shoot growth pattern exhibited similarity only with PB 1850-27. The F2 population exhibited segregation for mean root and shoot length.
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Chen, Bin, Guangfa Hu, Songlin Sun, Mingtao Xiao, and Chaoran Sun. "Design and Experimental Study of Intermittent Automatic Grouping Dropping Plug Seedling Mechanism of Fixed Seedling Cups." Applied Sciences 12, no. 21 (2022): 11125. http://dx.doi.org/10.3390/app122111125.
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In a vegetable transplanting operation, if the seedling picking mechanism extracts the whole row of seedlings, the seedling separating mechanism needs to place the seedlings in groups. In this study, a seedling separating mechanism based on a fixed seedling cup was proposed to realize faster seedling grouping in a smaller volume. A collision model between the pot and the wall of the seedling dropping cylinder during the seedling dropping process was established. The duration of seedling dropping at different positions was analyzed. Subsequently, the calculation equations between the installation angle and the cam rotation speed and the dropping duration were derived. The net dropping duration of seedlings at different positions was measured. According to the measurement results, the installation angles of the driving cam at each position were calculated as 0°, 72°, 150°, 216°, and 288°, respectively. The seedling uniformity test was conducted according to the optimized installation angles. The test results revealed that the success rate of dropping seedlings was 100%, the coefficient of variation in dropping seedling interval at different positions was 6.25%, and the matrix damage rate was less than 10%, which verified the reliability of the dropping seedling principle. Finally, the stability tests results showed that the mechanism was able to complete the uniform seedling drop operation at a seeding frequency of 75~108 plants/ (min · row) under the existing installation conditions. Therefore, the research results can provide a reference for the design and research of a subsequent traction-based automatic pot seedling transplanting machine.
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Couvillon, Gary A. "Cercis canadensis L. Seed Size Influences Germination Rate, Seedling Dry Matter, and Seedling Leaf Area." HortScience 37, no. 1 (2002): 206–7. http://dx.doi.org/10.21273/hortsci.37.1.206.
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Several studies with annual crops have shown that large seeds improve percent germination, seedling growth, and uniformity, yield, seedling vigor, and stress tolerance. Little information is available on the influence of seed size on the resulting seedlings of woody plant species. Cercis canadensis L. seeds were divided into large and small seed size fractions and the seeds scarified, stratified, and planted. A larger percentage of large seeds germinated than did small seeds. Seedlings from large seeds had a greater peak and germination value than small seeds, indicating greater vigor and a more rapid germination rate thus more uniform seedlings. Seedlings from large seeds, as indicated by fresh and dry weights, were larger and contained a greater leaf area than those produced by small seed.
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Anwar M, Hossen, Hossain Mosharraf M, Haque Enamul M, and Bell Richard W. "Effect of growing media on mat type seedling raised for mechanical rice transplanting." Research in Agricultural Engineering 64, No. 3 (2018): 157–67. http://dx.doi.org/10.17221/79/2016-rae.
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Mechanical transplanted seedling must meet the requirements of standard seedling block with uniform distribution of seedlings and inter-twisting roots for rolling. This study was conducted to identify the effect of growing media on mat type seedling raised for mechanical transplanting at Bangladesh Rice Research Institute (BRRI), Gazipur during the period of 2012–2014 covering two dry and cold seasons (Boro) and one wet season (Aman). Seedling were raised on plastic tray using sandy loam and clay loam soil mixed with decomposed cow-dung, mustard cake, rice straw organic fertilizer, rice bran, poultry litter and vermicompost at the rate of 0.0, 10, 20, 30 and 40%. Rolling quality of the seedling mat decreased and seedling height increased with the increased of mixing rate of organic fertilizer except rice bran and mustard cake. Averaged across three seasons, 10 to 30% cow-dung, rice straw organic fertilizer, vermicompost, 10% poultry litter and 20 to 30% rice bran with both types of soil was found suitable for seedling mat and seedling height. However, seedling varied among the organic fertilizers with both types of soil in the order of cow-dung > rice bran > vermicompost > poultry liter > rice straw organic fertilizer > mustard cake. Clay loam soil showed better performance on rolling quality over sandy loam soil.
14
Bhuiyan, MAH, ME Ali, MR Khatun, F. Alam, and MB Banu. "Effect of Arbuscular Mycorrhizal Inoculum Rate on Tomato (Lycopersicum esculenta L.) Seedlings." Bangladesh Journal of Microbiology 29, no. 2 (2016): 104–8. http://dx.doi.org/10.3329/bjm.v29i2.28444.
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An experiment on the effect of rate of arbuscular mycorrhiza inoculum in producing tomato seedlings (var. Ratan) were conducted in the seedbed of Soil Science Division, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur, Bangladesh during rabi season of 2007-08 and 2008-09. Seven rates of AM inoculum viz. 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 kg m-2 were studied on tomato seedlings. Cowdung was used at the rate of 5 kg m-2 as basal. Seeds were sown in 10 cm apart solid lines on 13 November 2007 and 11 November 2008, and the seedlings were thinned down to about 3 cm from seedling to seedling within a week of germination. Ratan was used as the variety of tomato. Biomass yield, seedling height and nutrient uptake by tomato seedlings increased greatly with the use of AM inoculum. Biomass yield of tomato seedlings followed quadratic trend with the increase of AM inoculum rate from 0 to 1.0 kg m-2 in 2007-08 and 0 to 2.0 kg m-2 in 2008-09.Bangladesh J Microbiol, Volume 29, Number 2, Dec 2012, pp 104-108
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Wen, Yongshuang, Leian Zhang, Xuemei Huang, et al. "Design of and Experiment with Seedling Selection System for Automatic Transplanter for Vegetable Plug Seedlings." Agronomy 11, no. 10 (2021): 2031. http://dx.doi.org/10.3390/agronomy11102031.
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In the process of vegetable plug seedling cultivation, packaging, and transportation, there may be missing, unhealthy or injured seedlings in the tray, which results in a missed planting or a low seedling survival rate after automatic transplanting. In this study, a seedling selection system with the function of seedlings identification, week seedlings elimination, and missing seedlings supplement was developed for an automatic transplanter. A plug seedling identification system based on a machine vision was used to detect vegetable plug seedlings based on the area characteristics of plug seedlings, stem leaves and plug bodies. The identification results were transmitted to a programmable logic controller (PLC), which controlled a nozzle to eliminate the unqualified seedlings from the conveyor belt lattice. When the empty conveyor belt lattice reaches the seedling throwing funnel, the rear conveyor belt lattice with the plug seedling is accelerated to ensure the continuity of seedlings supply. The adaptive fuzzy PID control algorithm was used to control the stepper motor of the conveyor belt to realize accurate seedling conveying and a seedling supplement. Using 30 days pepper plug seedlings as experimental seedlings, a comparative field experiment was carried out to evaluate the performance of the seedling selection system. The results showed that when the seedling selection system was turned on and the seedling extracting frequencies were 60, 80, and 100 plants/min, the success rates of plug seedling identification were 98.84%, 98.38%, and 96.99%, and the robust seedling rates were 98.05%, 97.78%, and 95.83%. The robust seedling rates were increased by 15.64%, 16.07%, and 13.89%, respectively, in contrast to turning off the seedling selection system.
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Mao, Hanping, Guoxin Ma, Luhua Han, Jianping Hu, Feng Gao, and Yang Liu. "A whole row automatic pick-up device using air force to blow out vegetable plug seedlings." Spanish Journal of Agricultural Research 18, no. 4 (2021): e0211. http://dx.doi.org/10.5424/sjar/2020184-17003.
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Aim of study: To develop a whole row automatic pick-up device using air force to blow out plug seedlings, to avoid the damage to seedlings that the current way of seedling picking by needle insertion induces.Area of study: Jiangsu Province, China.Material and methods: We designed a pick-up device which mainly consists of a seedling transporting device, a seedling air loosening device, a seedling clamping device and an automatic control system. The damage rate of seedling was significantly reduced and the success rate of seedling picking was increased by using the new seedling air loosening method and the new designed end-effectors. A prototype of the new pick-up device was produced according to the calculation results, and the performance tests were arranged under actual production conditions in an indoor laboratory.Main results: The calculation showed that when the diameter of the blowhole in air nozzle is 3.5 mm, and the air pressure is between 0.146 MPa and 0.315 MPa, the seedlings can be blown out successfully. Besides, the clamping strain test showed that the new designed end-effector can meet the requirements of seedling picking. The orthogonal test showed that both the air pressure and water content significantly affected the success ratio. The success ratio reached 96.64% when air pressure was 0.4 MPa, water content was 55%-60% and airflow rate was 100%, what meets the current requirements of transplanting.Research highlights: This research can provide some references for the automatic transplanting technology.
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Periasamy, Vivek, Duraisamy, and Kavitha. "Development of a picking and dropping mechanism for protray grown vegetable seedlings." Journal of Applied and Natural Science 13, SI (2021): 47–54. http://dx.doi.org/10.31018/jans.v13isi.2776.
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In India, manual transplanting of vegetable seedlings was the commonly adopted method for raising vegetable crops, but it is laborious, time-consuming and costly. Therefore, mechanical transplanters are developed to overcome the problems in manual transplanting. The present work was to develop multiple seedlings picking and transferring mechanism for protray grown vegetable seedlings. Tomato (Solanum lycopersicum), chilli (Capsicum annuum) and brinjal (Solanum melongena) seedlings were raised in portrays with coir pith as a growth media and used for transplanting operation. The mechanism was to pick seven numbers of seedlings in one row at a time and transfer them into lateral conveying system, which could deliver the seedlings one by one on to the ground at regular interval. Programmable Logic Controller was used to controlling entire operations of seedlings picking and dropping. At the time of evaluation, a totally 196 number of seedlings were used with 98 cell protray. From the test results, the success rate of 89.28 per cent, missing seedling of 3.57 per cent, damaged seedling of 4.08 per cent, seedling delivering failure of 3.06 per cent were recorded for tomato seedlings. Similarly, in chilli and brinjal the success rate of 95.40 and 91.83 per cent, the missing seedling of 2.04 and 2.55 per cent, damaged seedling of 1.53 and 3.06 per cent and seedling delivering failure of 1.02 and 2.55 per cent respectively were observed. Transplanting frequency of developed mechanism was 2520 seedlings h-1. As a whole, this work was able to develop a working model of vegetable seedling transplanting mechanism, which can eject seven seedlings at a time from portray cell and transfer them into the slotted conveyor.
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Zuo, Qingsong, Jingjing You, Long Wang, et al. "A Balanced Sowing Density Improves Quality of Rapeseed Blanket Seedling." Agronomy 12, no. 7 (2022): 1539. http://dx.doi.org/10.3390/agronomy12071539.
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Mechanized transplanting of rapeseed (Brassica napus L.) blanket seedling is an effective strategy to cope with the seasonal conflict and large labor cost in rapeseed production. The sowing density is a key factor to cultivate high-quality seedlings suitable for mechanized transplanting. An experiment was conducted to investigate the effects of different sowing density levels of 638, 696, 754, 812, 870 and 928 seeds per tray (referred as D1, D2, D3, D4, D5 and D6, respectively) on agronomic traits and survival rate after mechanized transplanting of two rapeseed cultivars (Zheyouza108 and Heza17) in 2020 and 2021. The results showed that high sowing density increased plant height but decreased leaf area, collar diameter, biomass accumulation, the ratio of root to shoot and seedling fullness. These negative effects jointly decreased the seedling rate and survival rate after mechanized transplanting. However, the seedlings under D1 and D2 posed a great plant survival rate of more than 95% after mechanized transplanting, suggesting that the seedlings under the two densities were perfect for mechanized transplanting. In addition, hierarchical analysis grouped D1 and D2 into the same class, indicating that their seedling qualities were not significantly different, though the blanket seedlings under D1 outperformed those under D2 in some traits. A sowing density of 696 seeds per tray (D2) is then recommended in this study, altogether considering its high-quality seedlings suitable for mechanized transplanting, and economically, fewer seedling trays required.
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M.G. Nayak and G.S. Mohana, Babli Mog, J. D. Adiga. "Germination and seedling establishment in cashew (Anacardium occidentale L.): An interaction between seed size, relative growth rate and seedling biomass." Journal of Plantation Crops 45, no. 2 (2017): 110. http://dx.doi.org/10.19071/jpc.2017.v45.i2.3305.
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<p>Seeds of cashew were used to determine the effect of seed mass (5.2 to 7.8 g) on germination, seedling emergence and growth<br />under nursery conditions. Germination percentage and germination time showed significant correlation with seed mass. Large<br />sized seeds had higher germination percentage (81.6%) and produced more vigorous seedlings. Per cent seedling emergence was<br />related to seed mass with large sized seeds exhibited faster emergence. Seed mass significantly affected seedling survival and<br />survival rate was high in seedlings arising from large sized seeds (62.9%). Seedling vigor expressed in terms of shoot and root<br />length, leaf number, leaf area and total dry matter was significantly affected by seed mass. Seedlings that emerged from large sized<br />seeds showed better growth and produced heavier seedlings as compared to medium sized seeds. RGR showed significant variation<br />(0.152 to 0.240 g g-1day-1) among two seed size classes positively correlated with seed mass, leaf area (LA), unit leaf rate per unit<br />leaf area (ULRM), root to shoot ratio (R/S) and root mass ratio (RMR) and negatively with stem mass ratio (SMR). The study<br />concluded that the seed mass and RGR have influence on seedling growth and success of seedling establishment in cashew.</p>
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Zhang, Ni, Guozhong Zhang, Haopeng Liu, Wanru Liu, Jia Wei, and Nanrui Tang. "Design of and Experiment on Open-and-Close Seedling Pick-Up Manipulator with Four Fingers." Agriculture 12, no. 11 (2022): 1776. http://dx.doi.org/10.3390/agriculture12111776.
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With the aim to solve the problems of plug seedlings being damaged and the low success rate in the process of picking up seedlings, an open-and-close seedling picking manipulator with four fingers was designed. The clamping scheme with quadrangle inserting while clamping was designed in order to reduce the disturbance and injury of pot matrix soil. The working principle of the manipulator was expounded, and a mathematical model of the mechanism movement was established. The force transmission of the mechanism and force between finger and pot was analyzed, and the constraint condition of optimum force transmission efficiency and low damage when picking up seedlings was analyzed. Based on theoretical calculation and analysis, a set of optimal parameters and the trace curve of the finger end point were obtained. Based on the above theoretical calculation, kinematics parameters were analyzed and verified by Adams software. IF and STEP velocity functions were used to define the motion form of the driving source to simulate manipulator opening away from the seedling, straight down near the seedling, inserting into pot while clamping, and lift-off after the insertion to depth 45 mm. The simulation result proved the end point trajectory obtained by the motion simulation was basically consistent with that obtained by theoretical calculation. Velocity and acceleration curves of each mechanism component were obtained, and the result proved the velocity and acceleration of the tip of the finger changed greatly, and the inertia impact was large; the inertia force helped to clamp the pot. The manipulator was installed at the end of the transplanting platform. A plug seedling of “Zhongnong Luheng line pepper 363” was taken as the object, and the pot moisture content, seedling pick-up frequency, and finger material were used as experimental factors for the seedling pick-up test. The results showed that the above three factors had significant effects on the rate of pot damage and the rate of successful seedling pick-up. The optimum level was that when the moisture content was 45%, the frequency of picking seedlings was 20 plants·min−1, and the clamping finger material was carbon steel; the damage rate of the pot body was 1.98%, and the success rate of picking seedlings was 98%. This manipulator has the advantages of stable seedling picking and a low damage rate and can be used for transplanting plug seedlings of plants such as pepper and tomato.
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Eshetu, Reta, Mesafint Minale, and Abeje Tedila. "Assessment of Factors Hindering Seedling Survival at Ankober Woreda, North Shewa Zone." Forest Research: Open Access 12, no. 1 (2023): 4. https://doi.org/10.35248/2168-9776.22.12.336.
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Tree planting in Ethiopia has been developed as a strategy to mitigate the negative effects of environmental change. However, this strategy has been challenged by failure or low survival of seedlings at field condition due to a number of factors. Hence, this study focused on assessing biotic, abiotic, and institutional factors that influence the survival of seedlings. The result revealed that 94.64 % of the respondents produced bare rooted seedlings; due to lack of plastic bag. According to respondents, factors that hinder seedling survival in the study area were: Insects (64%), frost (88%) and less attention given by government on pit digging and moisture retention preparation, seedling management and species selection without basic information. Therefore, special attention should be given on supplying, introducing and selecting tree species with basic information. Moreover, adequate management, proper follow up, monitoring and evaluation system must be designed to increase the survival rate of planted seedlings.
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Kim, Hyeonji, Heejae Jo, Gwang-Jung Kim, Hyung-Sub Kim, and Yowhan Son. "Effects of Spring Warming and Drought Events on the Autumn Growth of Larix kaempferi Seedlings." Water 14, no. 12 (2022): 1962. http://dx.doi.org/10.3390/w14121962.
Full textAbstract:
High temperatures and droughts following winter dormancy can negatively affect seedling growth and mortality. An open-field experiment was conducted to study the growth and mortality of Larix kaempferi seedlings in response to spring warming and drought treatments and to determine whether seedlings could regain their growth capability once the treatments were discontinued. In May 2020, 1-year-old seedlings were exposed to four treatments: control, warming-only, drought-only, and the combined warming and drought. Drought treatment reduced the seedling height and root collar diameter and increased the mortality rate. The combined warming and drought treatments had the highest mortality rates, followed by the drought, control, and warming treatments. However, after the cessation of the treatments, the combined warming and drought treatments increased seedling height, root collar diameter, and individual seedling biomass because the high mortality rate relaxed competition among seedlings. This suggests that the effects of low competition on the surviving seedlings may mitigate the negative effects of warming and drought on seedling growth. Our study demonstrates that despite the high mortality and decreased growth during the treatment period, seedlings subjected to combined high temperature and drought stress showed short-term high levels of growth compared to seedlings subjected to a single stress.
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Moore, James A., Zhaofei Fan, and Bahman Shafii. "Effect of Root-Plug Incorporated Controlled-Release Fertilizer on Two-Year Growth and Survival of Planted Ponderosa Pine Seedlings." Western Journal of Applied Forestry 17, no. 4 (2002): 216–19. http://dx.doi.org/10.1093/wjaf/17.4.216.
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Abstract Three controlled-release fertilizers (fast release [FR], moderate release [MR], and slow release [SR]) were incorporated in the root plug at rates of 0.8, 1.6, or 3.2 g/seedling at the time of sowing as supplements to nursery supplied soluble fertilizer. Effects on seedling growth, survival, and foliar nutrient status of the “160/90” container ponderosa pine (Pinus ponderosa) were evaluated after outplanting. At the end of the second growing season, fertilized seedlings had significantly greater diameter and height than unfertilized seedlings. The 3.2 g of MR or SR fertilizer treatments produced significantly higher mortality (55 and 36%, respectively) than the controls. The fast release fertilizer included at a rate of 0.8 g in each seedling's container was the preferred treatment since it produced good survival and seedling growth response. A 2-yr growth response of about 25% was similar to that observed in a nearby study using adjacent placement of controlled-release fertilizer after planting ponderosa pine seedlings. West. J. Appl. For. 17(4):216–219.
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Lin, Jiaqi, Dongling Li, Zhenghui Pan, Dou Feng, and Weiyan Xuan. "Effect of the Floating Seedling Technique on Banana Seedling Growth." HortScience 57, no. 3 (2022): 458–63. http://dx.doi.org/10.21273/hortsci16303-21.
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Floating seedling technology was used to propagate banana seedlings. The effects of different substrates, such as wood bran, vermiculite, and Murashige and Skoog (MS) nutrient solution, at different concentrations on the survival rate of banana floating seedlings and the growth of seedling stem, leaf, and root systems were compared. The results showed that banana seedlings treated with MS nutrient solution at one-half or one-third concentration or hydroponically with controlled slow-release fertilizer (0.5–0.6 g/plant) directly added to the wood bran substrate grew the fastest and had the largest number of roots. At 50 days after transplanting, these banana seedlings reached the standard of first-grade packaged seedlings, with the number of expanded leaves reaching 6.6 to 7.6, the width of leaves reaching 6.5 cm to 7.3 cm, and the root system relatively developed. The comprehensive characteristics of the seedlings were all better than those of other treatments. The results of this study have certain reference significance for accelerating seedling growth in greenhouses and large-scale production of disease-free banana seedlings. The banana floating seedling system we developed did not need watering every day and may be simpler than other seedling raising methods.
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Yue, Rencai, Jianping Hu, Yijun Liu, Mengjiao Yao, Tengfei Zhang, and Jiawei Shi. "Design and Working Parameter Optimization of Pneumatic Reciprocating Seedling-Picking Device of Automatic Transplanter." Agriculture 12, no. 12 (2022): 1989. http://dx.doi.org/10.3390/agriculture12121989.
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To improve the seedling-picking efficiency of the vegetable transplanter and reduce the damage rate of the seedling pot, a reciprocating seedling-picking device driven by full air pressure was designed. In this paper, the structure and working principle of the pneumatic seedling-picking device are introduced. Through the mechanical analysis between the seedling-picking claw and the seedling pot, working parameters such as the stroke and driving force of the pneumatic seedling-picking claw clamping cylinder were determined. According to the action sequence of the seedling-picking mechanism, which is horizontally dispersed and longitudinally conveyed, the pneumatic control scheme of the seedling-picking and -dropping system was formulated. The simulation model for the control loop of the longitudinal cylinder was created with AMESim simulation software, and the simulation analysis was carried out. The Box–Behnken response surface design optimization method was used to determine the best operating parameters of the cylinder. The optimized peak value of shock vibration at the end of the cylinder was optimized from −65.64 mm·s−2 to 35.41 mm·s−2, proving that the optimization of pneumatic working parameters has a positive effect on the success rate of seedling picking. The bench test of the seedling-picking mechanism was conducted on 72-hole plug seedlings with two picking frequencies of 120 plants·min−1 and 144 plants·min−1, respectively, and the average seedling leakage rate, seedling damage rate, and seedling pot damage rate at different picking frequencies were counted. The experimental results show that under the two seedling-picking frequencies, the average success rate of seedling picking and throwing after optimization is increased from 96.4% and 92.4% to 97.9% and 95.3%, respectively. This is in line with the requirements of high-speed seedling picking and confirms the rationality of the seedling-picking mechanism design.
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Dong, Liqiang, Tiexin Yang, Rui Li, Liang Ma, Yingying Feng, and Yuedong Li. "Grain Yield, Rice Seedlings and Transplanting Quantity in Response to Decreased Sowing Rate under Precision Drill Sowing." Agriculture 14, no. 10 (2024): 1745. http://dx.doi.org/10.3390/agriculture14101745.
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Mechanical transplanting has become an important part of modern Chinese rice production, and an inadequate sowing rate severely inhibits rice seedling growth and development. Precision drill sowing is an effective method for obtaining higher quality seedlings during machine transplanting. There is a lack of systematic research on the precision drilling of rice. Therefore, we carried out research on the quality of machine-transplanted seedlings and precision drill sowing transplantation. A greenhouse experiment (Liaoning Rice Research Institute) and field experiment (Sujiatun District, Shenyang City, Liaoning Province, China) were conducted between 2020 and 2021 to analyze the influence of precision drill sowing on rice growth and yield. Precision drill sowing was conducted at four sowing rates (3400, 3600, 3800, and 4000 seeds/tray), and traditional broadcasting was also conducted at a sowing rate of 4000 seeds/tray. We evaluated the seedling rice quality, physiological and biochemical characteristics and transplanting quantity. The results indicated that precision drill sowing at a sowing rate of 3400 seeds/tray resulted in the highest plumpness value (0.18) and seedling strength index (0.42) of individual plants. However, the empty hill rate was as high as 3.05%, which did not satisfy the field seedling number requirement. Precision drill sowing at a sowing rate of 4000 seeds/tray resulted in the lowest physiological (the average levels of SOD, POD and soluble protein were 311.78 µg/g, 8.25 µg/g and 1.28 µg/g) and biochemical indices of individual plants. The damaged seedling rate increased by 2.07%, and the dead seedling rate increased by 0.25%, resulting in poor seedling and transplanting quality. In this study, 3800 seeds/tray was the best option and had the highest yields of 10,776.60 kg/ha and 10,730.85 kg/ha over the two years. This sowing approach performs well in terms of field transplanting, provides a balance point between seedling number and quality and is conducive to rice yield production. The results of this study are important for improving rice seedling quality, enhancing field transplanting quantity and increasing rice yield and food security.
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Gao, Min, Fengbao Yang, Hong Wei, and Xiaoxia Liu. "Automatic Monitoring of Maize Seedling Growth Using Unmanned Aerial Vehicle-Based RGB Imagery." Remote Sensing 15, no. 14 (2023): 3671. http://dx.doi.org/10.3390/rs15143671.
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Accurate and rapid monitoring of maize seedling growth is critical in early breeding decision making, field management, and yield improvement. However, the number and uniformity of seedlings are conventionally determined by manual evaluation, which is inefficient and unreliable. In this study, we proposed an automatic assessment method of maize seedling growth using unmanned aerial vehicle (UAV) RGB imagery. Firstly, high-resolution images of maize at the early and late seedling stages (before and after the third leaf) were acquired using the UAV RGB system. Secondly, the maize seedling center detection index (MCDI) was constructed, resulting in a significant enhancement of the color contrast between young and old leaves, facilitating the segmentation of maize seedling centers. Furthermore, the weed noise was removed by morphological processing and a dual-threshold method. Then, maize seedlings were extracted using the connected component labeling algorithm. Finally, the emergence rate, canopy coverage, and seedling uniformity in the field at the seedling stage were calculated and analyzed in combination with the number of seedlings. The results revealed that our approach showed good performance for maize seedling count with an average R2 greater than 0.99 and an accuracy of F1 greater than 98.5%. The estimation accuracies at the third leaf stage (V3) for the mean emergence rate and the mean seedling uniformity were 66.98% and 15.89%, respectively. The estimation accuracies at the sixth leaf stage (V6) for the mean seedling canopy coverage and the mean seedling uniformity were 32.21% and 8.20%, respectively. Our approach provided the automatic monitoring of maize growth per plot during early growth stages and demonstrated promising performance for precision agriculture in seedling management.
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S.H.S. Senarathne. "Effect of Arbuscular Mycorrhizal Fungi Based Biofertilizer on Coconut Seedlings Growth in Nursery." CORD 34, no. 2 (2018): 12. http://dx.doi.org/10.37833/cord.v34i2.17.
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The success of a coconut plantation, in terms of its field establishment as well as its future performance, is heavily dependent on the quality of the seedlings used. Coconut nurseries adopt different agronomic practices to produce good quality seedlings. Applying mycorrhizal inoculants is becoming an increasingly common practice in plant nurseries as it facilitates healthy seedling growth resulting in healthy and vigorous seedlings in the nursery, helps to reduce mortality rates of seedlings in the field and reduce water and fertilizer consumption. In this study effects of mycorrhizae based biofertilizer were evaluated for the growth of coconut seedlings in the nursery and field. The experiment was conducted at the Makadura Research Center in Sri Lanka. The nursery experiment treatments were, the presence of AMF based biofertilizer (50g per seedling or per bag) and absence of mycorrhizae based biofertilizer. In the field experiment, five treatments with 500g of AMF biofertilizerwith 25% recommended inorganic fertilizer mixture for young coconut palms (YPM) per seedling, 500g of AMF biofertilizer with 50% YPM per seedling, 500g of AMF biofertilizer with 75% YPM per seedling, 500g of AMF biofertilizer with 100% YPM per seedling and with only YPM per seedling. Root and shoot growth of seedlings were measured at monthly intervals in the nursery experiment. Leaf production rate and stem girth of the seedling were measured at six months interval in the field experiment. The application of bio fertilizer increased the volume and dry weight of primary, secondary, tertiary and quaternary roots in seedlings in the nursery significantly. A significantly higher leaf production rate and stem girth was observed in the field seedlings treatment with 500g of AMF biofertilizer with 75% YPM. The experiment concluded that application of bio fertilizer is beneficial for coconut seedlings in the nursery for the production good quality seedlings with well-developed roots resulting in better field establishment and in the field for fast and vigorous growth.
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Ren, Lipeng, Changchun Li, Guijun Yang, et al. "The Detection of Maize Seedling Quality from UAV Images Based on Deep Learning and Voronoi Diagram Algorithms." Remote Sensing 16, no. 19 (2024): 3548. http://dx.doi.org/10.3390/rs16193548.
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Assessing the quality of maize seedlings is crucial for field management and germplasm evaluation. Traditional methods for evaluating seedling quality mainly rely on manual field surveys, which are not only inefficient but also highly subjective, while large-scale satellite detection often lacks sufficient accuracy. To address these issues, this study proposes an innovative approach that combines the YOLO v8 object detection algorithm with Voronoi spatial analysis to rapidly evaluate maize seedling quality based on high-resolution drone imagery. The YOLO v8 model provides the maize coordinates, which are then used for Voronoi segmentation of the field after applying the Convex Hull difference method. From the generated Voronoi diagram, three key indicators are extracted: Voronoi Polygon Uniformity Index (VPUI), missing seedling rate, and repeated seedling rate to comprehensively evaluate maize seedling quality. The results show that this method effectively extracts the VPUI, missing seedling rate, and repeated seedling rate of maize in the target area. Compared to the traditional plant spacing variation coefficient, VPUI performs better in representing seedling uniformity. Additionally, the R2 for the estimated missing seedling rate and replanting rate based on the Voronoi method were 0.773 and 0.940, respectively. Compared to using the plant spacing method, the R2 increased by 0.09 and 0.544, respectively. The maize seedling quality evaluation method proposed in this study provides technical support for precision maize planting management and is of great significance for improving agricultural production efficiency and reducing labor costs.
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Fu, Wei, Jinqiu Gao, Chunjiang Zhao, Kai Jiang, Wengang Zheng, and Yanshan Tian. "Detection Method and Experimental Research of Leafy Vegetable Seedlings Transplanting Based on a Machine Vision." Agronomy 12, no. 11 (2022): 2899. http://dx.doi.org/10.3390/agronomy12112899.
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In view of the need to remove empty cells and unqualified seedlings for automatic transplanting of leafy vegetable seedlings, this paper proposes a method to detect the growth parameters of leafy vegetable seedlings by using machine vision technology. This method uses the image processor PV200 to perform image grayscale, threshold segmentation, corrosion, expansion, area division, etc. to obtain the pixel value of the leaf area of the seedling and compare it with the set standard value, which provides guiding information for eliminating empty cells and unqualified seedlings. Lettuce seedlings at 17 days, 20 days, and 22 days of seedling age were used as the test objects, and the growth status and test results of the seedlings were analyzed to determine the optimum seedling age for transplanting. The test results show that there is basically no leaf cross-border between the lettuce seedlings at the age of 17 days, the average pixel area of the leaves is 3771.74, and the detection accuracy rate is 100%; the seedlings at the age of 22 days grow 5–6 leaves, the detection accuracy of unqualified seedlings and qualified seedlings was 62.50% and 88.16%, respectively, and the comprehensive detection accuracy was 85.71%. The comprehensive detection accuracy rate showed a downward trend with the increase of seedling age, mainly due to the partial occlusion between leaves. The transplanting of leafy vegetable seedlings is a sparse transplanting operation, and the seedling spacing increases after transplanting. Therefore, the detection of seedlings in the process of transplanting can greatly improve the recognition accuracy and solve the problem that the leaves of the seedlings in the seedling tray are obscured by each other and affect the detection accuracy. The research results can provide a theoretical basis and design reference for the development of the visual inspection system and the transplanting actuator of the leafy vegetable seedlings transplanting robot.
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Zhang, Min, Zhan Jiang, Lan Jiang, Chongyou Wu, and Yao Yang. "Design and Test of the Seedling Cavitation and Lodging Monitoring System for the Rape Blanket Seedling Transplanter." Agriculture 12, no. 9 (2022): 1397. http://dx.doi.org/10.3390/agriculture12091397.
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To realize the real-time monitoring of the lodging and cavitation state of the rape blanket seedling transplanter, a real-time online monitoring system set for cavitation and lodging based on machine vision was designed. The system was mainly composed of an image acquisition module, a height sensor, and an IPC (Industrial Personal Computer). When the system starts to work, the height of the lens from the ground and the collected images are saved in real time, and the operating status of the equipment is judged according to the height of the lens from the ground, and the actual corresponding size of the image pixels is corrected. We proposed a calculation method for judging the cavitation and lodging state of the seedlings based on the comparison between the actual planting position and the theoretical planting position of the seedlings. The processing and analysis software for the cavitation and lodging monitoring system of the rape blanket transplanter was compiled, and the monitoring system was developed. The dynamic test showed that the maximum absolute error of the cavitation recognition rate was 1.23%, and the maximum absolute error of the lodging recognition rate was 3.80%. The total time consumed of a 1 m image collected in real time from the collection, image processing and stitching, to seedling status recognition of the rape blanket seedling field was about 1 s. The accuracy and system processing time of the seedling cavitation and lodging state judgment can meet the accuracy and real-time requirements of cavitation and lodging state recognition for field transfer of rape blanket seedlings.
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Tanner, E. V. J., V. K. Teo, D. A. Coomes, and J. J. Midgley. "Pair-wise competition-trials amongst seedlings of ten dipterocarp species; the role of initial height, growth rate and leaf attributes." Journal of Tropical Ecology 21, no. 3 (2005): 317–28. http://dx.doi.org/10.1017/s0266467405002269.
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To investigate whether seedlings of ten dipterocarp species differed significantly in terms of growth and mortality or whether species were not significantly different and could be considered ecologically similar, seedlings were grown, two per pot, in two experiments: (1) where the two seedlings were of equal height (30 cm); and (2) where one seedling was 10 cm shorter than the other. Seedlings were grown in a shade house with 15% above-canopy light in a 50:50 forest soil–sand mixture and were watered frequently; pots were placed so that seedling density was 130 seedlings m−2 of ground. In the first experiment there were 45 pairwise combinations of species when seedlings were 30 cm tall (AB, AC, AD,…. BC, BD…IJ; where A, B, C…J signify different species); each combination was replicated 10 times so there were 450 pots with 900 seedlings. In the second experiment there were 100 pairwise combinations of species and size e.g. Aa (30 cm A with 20 cm a), Ab (30 cm A with 20 cm b), each combination was replicated 10 times hence there were 1000 pots with 2000 seedlings. After 22 mo 79% of the initial 2900 seedlings survived; on average they had grown 42 cm (i.e. to 72 cm tall from their initial 30 cm). The most frequent outcome of competition-trials between different sized individuals (784 of 1000 trials) was that the initially taller seedling of each pair ‘won’ (it was the taller or surviving seedling). When 900 of these trials (setting aside, Aa, Bb, Cc etc.) were analysed as 45 comparisons between species with different sized individuals (Ab and aB are one interspecific comparison for these purposes), initial height determined the outcome in 23 cases (even in some competitions between light hardwood species and heavy hardwood species); in 6 cases a species (mostly light hardwoods) behaved as a ‘dominant’ – they usually won even if they were smaller initially. We found few significant differences between species in: initial seedling heights; leaf nitrogen concentrations; and specific leaf areas when they were grown in similar conditions, and these attributes were not correlated with growth rates. The similarity of seedlings of different species meant that often a height difference of just 10 cm was enough to determine the outcome of a pairwise competition-trial in high seedling densities and light equivalent to that in forest gaps.
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Marx, Laura M., and Michael B. Walters. "Effects of nitrogen supply and wood species on Tsuga canadensis and Betula alleghaniensis seedling growth on decaying wood." Canadian Journal of Forest Research 36, no. 11 (2006): 2873–84. http://dx.doi.org/10.1139/x06-171.
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Eastern hemlock (Tsuga canadensis (L.) Carrière) and yellow birch (Betula alleghaniensis Britt.) in primary Michigan forests depend on decaying wood for seedling-establishment sites, but seedling densities vary across wood species (hemlock, yellow birch, and sugar maple (Acer saccharum Marsh.)). We collected seedlings and wood from a natural field experiment and conducted a companion greenhouse experiment to determine whether seedling mass and nitrogen (N) content varied with wood species and whether they were related to wood inorganic N supply. Yellow birch seedlings were largest on hemlock wood in the field (P = 0.003) and greenhouse (but P > 0.05), while hemlock seedling mass did not vary across wood species. N concentration and N mineralization rate varied by species (N concentration: hemlock < yellow birch < maple; N mineralization rate: hemlock > yellow birch ≈ maple), but neither seedling mass nor N content was significantly correlated with wood inorganic N supply. In the greenhouse, yellow birch seedlings responded to fertilization with N when growing on hemlock and maple but not yellow birch wood and appear to be limited by phosphorus when growing on yellow birch wood. We conclude that yellow birch seedling growth varies with wood species, and is limited by both N and phosphorus, while hemlock seedlings are unresponsive to variation in wood species during the first two growing seasons.
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Liu, Zhicheng, Lu Shi, Zhiyuan Liu, et al. "Design and Testing of a Seedling Pick-Up Device for a Facility Tomato Automatic Transplanting Machine." Sensors 24, no. 20 (2024): 6700. http://dx.doi.org/10.3390/s24206700.
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At present, tomato transplanting in facility agriculture is mainly manual operation. In an attempt to resolve the problems of high labor intensity and low efficiency of manual operation, this paper designs a clip stem automatic transplanting and seedling picking device based on the yolov5 algorithm. First of all, through the study of the characteristics of tomato seedlings of different seedling ages, the age of tomato seedlings suitable for transplanting was obtained. Secondly, the improved yolov5 algorithm was used to determine the position and shape of tomato seedlings. By adding a lightweight upsampling operator (CARAFE) and an improved loss function, the feature extraction ability and detection speed of tomato seedling stems were improved. The accuracy of the improved yolov5 algorithm reached 92.6%, and mAP_0.5 reached 95.4%. Finally, the seedling verification test was carried out with tomato seedlings of about 40 days old. The test results show that the damage rate of the device is 7.2%, and the success rate is not less than 90.3%. This study can provide a reference for research into automatic transplanting machines.
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Arnaud, Rodrigue Zongo. "Evaluation of the effectiveness of post-harvest conservation methods for seedlings of Solenostemon rotundifolius (Poir. J. K. Morton)." International Journal of Biosciences (IJB) 24, no. 5 (2024): 80–95. https://doi.org/10.12692/ijb/24.5.80-95.
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<em>Solenostemon rotundifolius is a </em>tuberous plant with great food and economic potential in Burkina Faso. One of the major problems in its production is the loss of seedlings during storage, resulting in a shortage of raw materials at planting time. The aim of this study was to assess the effectiveness of methods for preserving <em>S. rotundifolius </em>seedlings<em>. </em>A randomized block design with three (03) replicates was used. Twelve (12) preservation methods were tested. Measurements were made on the rate of budded seedlings, budding time, bud length and seedling loss rate. The results showed that six (6) conservation methods produced seedlings with a budding rate of over 80% and low seedling loss rates, ranging from 2.38% to 6.19%. These are: conservation in “Bitatoré” with millet husks as additive (BITA+G) with a seedling budding rate of 89.05 ± 2.27%, canaries with sand as additive (CAN+S) with a budding rate of 87.62 ± 2.17%, “Bitatoré” without additive (BITA) with a budding rate of 86,19 ± 2.33%, <em>Storage in Sand and Sprouting </em>(Tri S) with a budding rate of 85.71 ± 2.72%, canaries with wood shavings as additive (CAN+CB) with a budding rate of 85.24 ± 2.35% and canaries without additive (CAN) with a budding rate of 85.24 ± 2.54%. In addition, the seedlings produced by these methods had respective seed loss rates of 2.86%, 2.86%, 6.19%, 2.38%, 3.81% and 5.71%. The results also showed that seedling budding time varied from 51 ± 4 to 70 ± 3 days, depending on the storage method. published by the <strong> International Journal of Biosciences (IJB)</strong>
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McCreary, Douglas D., and Joe B. Zaerr. "Root respiration has limited value for assessing Douglas-fir seedling quality." Canadian Journal of Forest Research 17, no. 9 (1987): 1144–47. http://dx.doi.org/10.1139/x87-175.
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Root damage is a principal cause of poor seedling quality. Currently, the most widely used seedling-quality test measures a seedling's ability to initiate and elongate roots in a favorable environment; however, this test requires a lengthy response period and tedious, time-consuming measurements. Alternatively, the respiration rate of roots could be measured much more quickly and easily. Results of this study, which examined whether root respiration could successfully predict the survival and growth of potted Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings in a growth room, indicated that respiration may help assess root damage caused by desiccation but not that caused by freezing, hot storage, or rapid heating.
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Al-Mousawi, Muntadher Mohammed, Manar A. F. Hassan, Susan Mohammed Alrubaei, Zaid Khaleel Kadhim, and Maryam M. Salman. "Effect of Spraying Nano-Fertilizer (Loenergy Plus) and Hibiscus Extract on the Vegetative Growth Characteristics of the Seedling of Sour Orange Citrus aurantium L." IOP Conference Series: Earth and Environmental Science 1262, no. 4 (2023): 042029. http://dx.doi.org/10.1088/1755-1315/1262/4/042029.
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Abstract The experiment was carried out from the middle of March until the end of June in the greenhouse belonging to the Department of Horticulture and Landscape Engineering, the College of Agriculture, and the University of Karbala. To investigate the impact of spraying hibiscus extract and Nano-fertilizer (Loenergy Plus) on the vegetative growth traits of the seedling of the orange starting in 2022. The experiment was set up as a randomized complete block design (RCBD) with two factors: with Nano-fertilizer (Loenergy Plus) and hibiscus extract, each in three concentrations, and three replications, each with 18 seedlings and two seedlings each. Following the completion of the experiment, measurements were obtained, the outcomes were evaluated using the statistical design employed, and the averages were compared using the least significant difference test at the level of probability 0.05. The most significant findings were those of the Nano-fertilizer (Loenergy Plus) treatment, which at a concentration of 1.5 ml L-1 was significantly better than other concentrations in all growth characteristics studied (seedling height rate (cm), stem diameter rate (mm), average number of leaves (leaf /seedling), leaf area (cm2), average leaf chlorophyll content (SPAD unit), and shoot dry weight). Most of the growth characteristics that were examined (seedling height rate (cm), stem diameter rate (mm), average number of leaves (leaf/seedling), leaf area (cm2), rate of leaf chlorophyll content (SPAD unit), and shoot dry weight) were significantly improved by the application of hibiscus extract at an 8 g L-1 concentration. While the binary interaction between the two experimental factors (average seedling height (cm), average stem diameter (mm), average leaf chlorophyll content in leaves (SPAD unit), and shoot dry weight) had no significant effect, there was a significant effect of the bilateral interaction between the two experimental factors on the number of leaves (leaves / seedlings) and the leaf area (cm2).
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Blenis, Peter V., Kathleen L. Wiggins, James E. Cunningham, and Michael A. Pickard. "Maltol protects against infection of lodgepole pine seedlings by western gall rust." Canadian Journal of Forest Research 18, no. 12 (1988): 1658–60. http://dx.doi.org/10.1139/x88-252.
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Uptake and translocation of maltol into 6-week-old Pinusconforta (Engelm.) var. latifolia seedlings was followed by means of gas chromatography. Maltol concentrations of 6.0–7.3 mg/g seedling dry weight (46–55 μg/seedling) were observed over the first 3 days following a single application of 50 mg maltol/seedling. A split-plot design was used to determine if maltol could reduce seedling infection by Endocronartiumharknessii. Whole plots consisted of two inoculum levels (7 or 30 mg of spores per tray of seedlings) and subplots consisted of four levels of maltol (0, 2, 10, or 40 mg/mL) applied 2 days before inoculation to one-half tray of seedlings at the rate of 5 mL/cavity. The highest concentration consistently and significantly reduced seedling infection relative to the untreated control, although it also caused some phytotoxicity.
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Conner, Patrick. "Effect of Nitrogen Fertigation on First-year Pecan Seedling Growth." HortTechnology 17, no. 4 (2007): 491–95. http://dx.doi.org/10.21273/horttech.17.4.491.
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Pecan (Carya illinoinensis) seedling rootstocks require several years of growth in the nursery before they are large enough to graft. In this experiment, first-year pecan seedlings were fertigated with varying amounts of calcium nitrate in an attempt to stimulate growth rates. Pecan seedlings were fertigated every 2 weeks from May through October for a total of 10 applications. Total amounts of nitrogen (N) applied by fertigation were 0, 4, 10, 20, and 40 g of N per seedling. Leaf samples were taken after the fourth and tenth fertigations, and leaf elemental concentration was affected by fertigation rates. Seedling height and caliper were measured monthly. Seedling caliper continued to increase throughout the experiment, whereas height increase stopped in September. Seedling height and caliper were unaffected by N fertigation except for the N rate of 40 g, which suppressed seedling growth. These results suggest that the N needs of the seedlings were met by a preplant application of 50 lb/acre N applied as 10N–4.4P–8.3K.
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Conner, Patrick. "(130) Effects of Nitrogen Fertigation on First-year Pecan Seedling Growth." HortScience 41, no. 4 (2006): 1062D—1062. http://dx.doi.org/10.21273/hortsci.41.4.1062d.
Full textAbstract:
Pecan seedling rootstocks require several years of growth in the nursery before they are large enough to graft. In this experiment, first-year pecan seedlings were fertigated with varying amounts of calcium nitrate to stimulate growth rates. Pecan seedlings were fertigated every 2 weeks from May through October for a total of 10 applications. Total amounts of nitrogen (N) applied by fertigation were 0, 4, 10, 20, and 40 g of N per seedling. Leaf samples were taken after the fourth and 10th fertigation, and leaf elemental concentration was affected by fertigation rates. Seedling height and caliper were measured monthly. Seedling caliper continued to increase throughout the experiment, while height increase stopped in September. Seedling height and caliper were not affected by N fertigation except for the N rate of 40 g, which suppressed seedling growth. These results suggest that the nitrogen needs of the seedlings were met by a preplant application of 56 kg·ha-1 N applied as 10N–10P–10K.
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Andrade, Gisiane Camargo de, Cileide Maria Medeiros Coelho, and Matheus Santin Padilha. "Seed reserves reduction rate and reserves mobilization to the seedling explain the vigour of maize seeds." Journal of Seed Science 41, no. 4 (2019): 488–97. http://dx.doi.org/10.1590/2317-1545v41n4227354.
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Abstract: Understanding how the seed reserve dynamics occurs during germination and seedling formation is determinant for advancements on seed technology. The aims of this study were: to verify which accelerated ageing temperature is the most effective to separate the vigour levels of maize seeds and to evaluate the reserves dynamics during germination and seedling formation process. Seven maize cultivars were submitted to the germination rate, accelerated ageing, thousand seed weight, total seedling length, shoot and root length, dry matter of seed and seedling, remaining dry matter in the endosperm, seed reserves reduction rate, conversion efficiency of reserves, reserves mobilization rate to the seedling and energy expenditure using the completely randomized statistical design. The reserves dynamics and seedling formation depends on the genotype and the initial seed vigour. Accelerated ageing at 45 °C for 72 hours is the most efficient combination to segregate vigour levels. Genotypes with higher seed reserve utilisation efficiency have higher vigour, producing seedlings with higher dry matter, higher total, shoot and root length, regardless of seed weight. The two rates evaluated prompt us to conclude that they explain the maize seed vigour and can be used in quality control programs to select high physiological quality cultivars.
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Zhou, Maile, Zhaoxiang Wei, Zeliang Wang, Hao Sun, Guibin Wang, and Jianjun Yin. "Design and Experimental Investigation of a Transplanting Mechanism for Super Rice Pot Seedlings." Agriculture 13, no. 10 (2023): 1920. http://dx.doi.org/10.3390/agriculture13101920.
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Super rice contains a variety of advantageous characteristics. However, current rice seedling transplanting machines fail to achieve the necessary trajectory and distance required for super rice mechanized transplanting. To address this issue, this study introduces a differential-speed rotary mechanism for transplanting super rice pot seedlings. The developed mechanism operates using a non-uniform speed differential gear train, which enables the transplanting arm components to mimic the specific trajectory and posture necessary for transplanting super rice pot seedlings. The kinematic model of the differential-speed rotary super rice pot seedling transplanting mechanism (PSTM) was established, and optimization design software was developed. This software facilitated the determination of a set of mechanism parameters optimized for super rice pot seedling transplantation. The results obtained from virtual simulations were found to be in alignment with those from the optimization software, thereby verifying the accuracy of the theoretical analysis and simulation. A testing bench for the rice PSTM was also developed and used for pot seedling pickup experiments. The bench tests demonstrated that the designed super rice PSTM yielded a seedling pickup success rate of 97% and a seedling injury rate of 1.8% when operating at an efficiency of 200 times/min.
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Pathania, Ranu, J. Shekhar, S. S. Rana, and Saurav Sharma. "Assessment of physiological indices and energetics under different system of rice intensification in north western Himalayas." Journal of Applied and Natural Science 9, no. 4 (2017): 2372–76. http://dx.doi.org/10.31018/jans.v9i4.1540.
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Field experiment was conducted at the research farm of CSK Himachal Pradesh Krishi Vishvavidyalaya, Rice and Wheat Research Centre, Malan during kharif 2013 with the objective to select the best seedling age and spacing of rice under system of rice intensification in terms of energetic and employment generation for mid hill con-dition of Himachal Pradesh. The experiment was laid out in 3 times replicated split plot design, assigning of three seedling ages (10, 17 and 24 days) and two spacings (20 cm x 20 cm and 20 cm x 15 cm) in main plots and four seedling vigours corresponding to four seeding rates (25, 30, 35 and 40 g/m2) in sub plots. The leaf area per plant was significantly greater in 10 days seedling age and decreased with increase in age (P=0.05). Seedling rate did not affect leaf area index in all stages except 40 DAS when 35 g/m2 seeding rate had maximum LAI. Seedling age did not significantly influence crop growth rate at any interval but it did relative growth rate and net assimilation rate between 40-70 and 70-100 DAS (P=0.05). 24 days old seedling resulted in significantly higher relative growth rate and net assimilation rate between 40-70 DAS followed by 17 days old seedlings. Maximum value of energy input (13.23) was recorded in 24 days seedling. The energy use efficiency (Energy output: input) varied from 10.6 to 11.1 under different treatments. Wider spacing supporting less plant population consumed 10 man days less than closer spac-ing of 20 cm x 15 cm.
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Li, Wei, Jiacheng Li, Jia Wei, Chunda Niu, Deguang Yang, and Baiwen Jiang. "Response of photosynthesis, the xanthophyll cycle, and wax in Japanese yew (Taxus cuspidata L.) seedlings and saplings under high light conditions." PeerJ 11 (January 25, 2023): e14757. http://dx.doi.org/10.7717/peerj.14757.
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In order to understand the adaptative changes of the Japanese yew (Taxus cuspidate L.) to high light conditions, this study investigated gas-exchange, chlorophyll fluorescence, chlorophyll, and the impact of epicuticular wax on the gas-exchange and photoinhibition of Japanese yew seedlings and saplings. The chlorophyll content per unit area and photosynthetic rate in seedling leaves were significantly lower than in sapling leaves. When leaves from seedlings and saplings were exposed to 1,200 μmol·m−2·s−1 photon flux density (PFD) for 2 h, seedling leaves exhibited a greater down-regulation of maximum quantum yield (Fv/Fm) and actual photosystem II efficiency ($\Phi$PSII). Non-photochemical quenching (NPQ) and high energy quenching (qE) in sapling leaves were much higher than in seedling leaves when both were exposed to 1,200 μmol·m−2·s−1 PFD for 2 h. At a low level of O2, the photorespiration rate (Pr) and the ratio of photorespiration/gross photosynthetic rate (Pr/Pg) in seedling leaves were lower than in sapling leaves when both were exposed to 1,200 μmol·m−2·s−1 PFD, but this difference did not reach statistical significance (P < 0.05). Compared with sapling leaves, seedling leaves exhibited lower levels of xanthophyll pool. Epicuticular wax content on seedling leaves was significantly lower than on sapling leaves. The results of this study showed that wax coverage on the leaf surface decreased the photosynthetic rate in sapling leaves as a consequence of decreased stomatal conductance. Epicuticular wax is related to tree age and photoinhibition prevention in the Japanese yew. It is possible that lower photosynthetic rate, lower NPQ depending on the xanthophyll cycle, and lower deposition of epicuticular wax results in seedling plants that are not adapted to high light conditions.
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Şemun, TAYYAR, and YALÇIN Sevil. "The Influence of Ultraviolet-C Radiation on Seedling Growth of Cowpea (Vigna unguiculata (L) Walp.)." Journal of Scientific and Engineering Research 8, no. 3 (2021): 203–7. https://doi.org/10.5281/zenodo.10577667.
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<strong>Abstract</strong> This research was conducted to investigate the effects of ultraviolet-C (UV-C) radiation on seedling emergence and seedling growth parameters of cowpea seeds. The UV-C radiation treatments at different exposure times (0, 30, 60, 180 and 300 minutes) on the seeds were applied by using a ST 51 G/W 51UV tube with a wavelength of about 254nm. The control and UV-C treated seeds were sown in plastic boxes filled with experimental soil and incubated at optimum conditions. The seedling emergence rates (%), seedling height (cm), root length (cm), fresh and dry weights of seedlings (g) were determined. The maximum seed emergence rate was 86.6% for the seeds treated with UV-C for 60 minutes while the lowest was 83.3% for the control and 180 minutes UV-C treatment. The parameters ranged from 10.5±1.09­­–12.2±0.90 cm for seedling heights, 10.96±2.56–15.45±1.78 cm for root lengths, 1.015±0.07–1.106±0.11 g for fresh seedling weights and 0.064±0.004–0.080±0.012 g for dry seedling weights. Significant differences (p<0.05) were found for the values of seedling heights and root lengths. The seeds treated with 300 minutes resulted in the highest seedling heights and root lengths. As a result, future field experiments should be done to fully understand the effects of UV-C radiation on cowpea seeds.
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Arai, Nobumasa, and Tomohiko Kamitani. "Seed rain and seedling establishment of the dioecious tree Neolitsea sericea (Lauraceae): effects of tree sex and density on invasion into a conifer plantation in central Japan." Canadian Journal of Botany 83, no. 9 (2005): 1144–50. http://dx.doi.org/10.1139/b05-089.
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We studied the effects of differences in parent sex and density on seed rain and seedling and (or) sapling recruitment in a dioecious tree species (Neolitsea sericea (Bl.) Koidz.) with bird-dispersed seeds. We established four microhabitats: male or female trees inside or outside a single patch. The density of bird-disseminated seeds was significantly higher beneath females and inside the patch than beneath males and single trees outside the patch; this led to higher density of emerged seedlings inside the patch. The survival rate of germinated seedlings was also higher inside the patch than below single trees. In contrast, the survival rate of saplings was highest beneath males outside the patch, although very few seeds are dispersed beneath single males. Seedling and sapling recruitment beneath females and inside the patch will be accelerated owing to higher density of dispersed seeds, high seedling survival, and greater sapling density. In contrast, recruitment beneath males will be very slow. However, microhabitats beneath males are probably more suitable for seedling and sapling recruitment than microhabitats beneath females, since the survival rate of saplings was higher beneath males. Parental sex-biased seed rain and seedling and (or) sapling recruitment in dioecious plants may explain the regeneration pattern at a local scale.
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Tumpa, Katarina, Antonio Vidaković, Damir Drvodelić, et al. "The Effect of Seed Size on Germination and Seedling Growth in Sweet Chestnut (Castanea sativa Mill.)." Forests 12, no. 7 (2021): 858. http://dx.doi.org/10.3390/f12070858.
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The quantity and quality of seedlings in the nursery has an impact on the success of re-establishment and later growth. High germination rates enable a sufficient number of seedlings, and their quality is assessed using a number of parameters, including seedling height and root collar diameter. These parameters are influenced in some species by seed size, but the correlation between them is species-specific. The model species in this research was sweet chestnut (Castaneasativa Mill.), and seeds from 12 populations from two distinct biogeographical regions of Croatia were collected. We examined the influence of seed size on four parameters: germination rate, seedling height, root collar diameter and sturdiness quotient. Seed size has been shown to have a positive influence on both seedling height and root collar diameter, whereas no such correlation was noted for germination rate and sturdiness quotient. Significant differences in nut size and seedling growth parameters were found between the Mediterranean and continental populations, with higher values observed in the coastal Mediterranean populations. We concluded that seed origin and seed size have a significant impact on seedling growth and are important factors to consider when choosing seed material. Further nursery operations should consider seed origin and local environmental conditions when choosing seedlings for reforestation efforts and general forest operations.
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Gould, Nick, Tony Reglinski, Mike Spiers, and Joe T. Taylor. "Physiological trade-offs associated with methyl jasmonate - induced resistance in Pinus radiata." Canadian Journal of Forest Research 38, no. 4 (2008): 677–84. http://dx.doi.org/10.1139/x07-193.
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Methyl jasmonate (MeJA) can induce defence responses in plants to pathogen attack, but it can also have consequences for plant growth. The transient effects of exogenous MeJA treatment on the resistance of Monterey pine ( Pinus radiata D. Don) seedlings to Diplodia pinea (Desm.) Kickx. and some physiological parameters affecting the impact of treatment on seedling growth were investigated. Following foliar application of 4.5 mmol·L–1 MeJA, disease resistance was greatest 1–2 weeks after treatment and declined with time thereafter. Elevated disease resistance was accompanied by a reduction in seedling growth rate the second week following MeJA treatment. Thereafter, seedling growth rate recovered and exceeded that of the control seedlings 4–5 weeks after MeJA treatment. Within hours of MeJA treatment, reductions in both the capacity of photosystem II and transpiration rate were observed, resulting in a concomitant reduction in net CO2 uptake rate. The slight reduction in transpiration rate was also associated with an increase in needle water potential. Longer term measurements showed no effect of MeJA on photosynthetic rate, transpiration rate, chlorophyll content, or shoot water potential and thus could not account for the elevated growth rate observed 4–5 weeks after treatment.
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Thompson, T. E., and L. J. Grauke. "Pecan Tree Growth and Precocity." Journal of the American Society for Horticultural Science 128, no. 1 (2003): 63–66. http://dx.doi.org/10.21273/jashs.128.1.0063.
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Precocity of pecan [Carya illinoinensis (Wangenh.) C. Koch] seedlings (year of first fruit production) was studied in relation to original seed measurements (nut weight, buoyancy, volume, and density) and in relation to growth index (GI) measurements of seedling trees for 4 years. A total of 2,071 pecan seedlings, representing nine controlled-cross families, were studied. Original seed measurements were not related to precocity of resultant seedling trees; but seed weight, buoyancy, and volume were significantly correlated with seedling growth rates. Nut density was negatively related to growth of seedlings. These relationships show the importance of original seed measurements and seed parentage in determining seedling growth, and have direct relevance in pecan nursery operations to increase general rootstock seedling vigor. Seedling growth rate was significantly correlated to precocity levels, with measurements taken in the later years of the study showing the highest correlations with precocity. This strong growth-precocity relationship may have negative genetic implications since a common breeding objective is to produce more precocious cultivars that maintain smaller tree size in mature orchards.
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Thompson, T. E., and L. J. Grauke. "Pecan Tree Growth and Precocity." Journal of the American Society for Horticultural Science 128, no. 1 (2003): 63–66. https://doi.org/10.21273/jashs.128.1.63.
Full textAbstract:
Precocity of pecan [Carya illinoinensis (Wangenh.) C. Koch] seedlings (year of first fruit production) was studied in relation to original seed measurements (nut weight, buoyancy, volume, and density) and in relation to growth index (GI) measurements of seedling trees for 4 years. A total of 2,071 pecan seedlings, representing nine controlled-cross families, were studied. Original seed measurements were not related to precocity of resultant seedling trees; but seed weight, buoyancy, and volume were significantly correlated with seedling growth rates. Nut density was negatively related to growth of seedlings. These relationships show the importance of original seed measurements and seed parentage in determining seedling growth, and have direct relevance in pecan nursery operations to increase general rootstock seedling vigor. Seedling growth rate was significantly correlated to precocity levels, with measurements taken in the later years of the study showing the highest correlations with precocity. This strong growth-precocity relationship may have negative genetic implications since a common breeding objective is to produce more precocious cultivars that maintain smaller tree size in mature orchards.