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1

Ribeiro, J. L. P., M. L. Gregori, and L. C. Pardini. "Predição das propriedades elásticas de compósitos termoestruturais com reforço multidirecional." Matéria (Rio de Janeiro) 13, no. 1 (March 2008): 33–48. http://dx.doi.org/10.1590/s1517-70762008000100005.

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Os compósitos são uma classe de materiais que apresentam propriedades superlativas em relação aos materiais isotrópicos (metais, cerâmicos, polímeros), se considerarmos sua alta resistência aliada ao baixo peso. O reforço, a matriz e a interface entre ambos, definem o desempenho do componente em serviço e a temperatura de trabalho destes materiais. Particularmente, compósitos de uso a temperaturas superiores à 1000ºC são denominados de compósitos termoestruturais. Estes materiais suportam demandas termo-mecânicas significativas, sendo utilizados em gargantas de tubeira de foguetes, proteções térmicas re-irradiativas e materiais de fricção. Via de regra, esses materiais são manufaturados mediante a utilização de preformas fibrosas, que nada mais são que um "esqueleto" de reforço que translada resistência e rigidez ao material. A utilização de preformas permite a concepção e obtenção de componentes com geometrias complexas e dimensões as mais diversas, permitindo assim uma flexibilidade no projeto do componente a ser obtido. Embora apresentem virtudes incontestáveis, o custo desses materiais ainda é proibitivo para aplicações rotineiras. Também o custo dos testes mecânicos que validem suas propriedades em relação aos materiais de uso convencional torna-se oneroso, além de demandar equipamentos especiais. O presente trabalho aborda a predição das propriedades elásticas de compósitos termoestruturais de Carbono Reforçado com Fibras de Carbono (CRFC), com configurações de reforço tri-direcional (3D) e tetra-direcional (4D). As propriedades foram calculadas à temperatura ambiente para efeito de comparação ao grafite sintético, ainda utilizado em gargantas de tubeira de motores foguete de pequeno porte. Os cálculos de predição de propriedades elásticas foram baseados no método de homogeneização considerando a hipótese de mechas de fibras retas pela rigidez média ponderada.
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2

Becker Jr, Rudimar Cavalini, Felipe Felipe Zibetti, and Carlos Edmundo De Abreu E Lima Ipar. "ESTUDO DA ETAPA DE PERFURAÇÃO EM ÁGATA NO PROCESSO DE JATO DE ÁGUA ABRASIVA (AWJ)." Revista CIATEC-UPF 11, no. 1 (April 6, 2019): 55–69. http://dx.doi.org/10.5335/ciatec.v11i1.9294.

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O processo de usinagem por jato de água com abrasivo (AWJ) é uma importante ferramenta utilizada em praticamente todas as áreas industriais e apresenta inúmeras vantagens em relação a outros processos. O presente trabalho visa, de maneira experimental, investigar o efeito de alguns parâmetros de entrada do processo no tempo e qualidade final (diâmetros de entrada e saída) da peça durante a fase de perfuração inicial quando o material a ser cortado é ágata. Para isso, utilizou-se o método experimental de superfície de resposta para se identificar e quantificar o efeito que os fatores exercem sobre as variáveis de saída. Todos os parâmetros escolhidos como variáveis de entrada se mostraram influentes em pelo menos alguma das variáveis de saída, destacando-se a estratégia de perfuração e espessura do material para o tempo de perfuração e a estratégia de perfuração, a distância de afastamento da tubeira e a vazão mássica de abrasivo para os diâmetros de entrada e saída. Ainda, foram geradas as equações de regressão para as três variáveis de saída estudadas, tornando-se possível efetuar a sua predição com base nos valores escolhidos das variáveis de entrada.
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3

Vernon, Robert S., and Donald R. Thomson. "OVERWINTERING OF TUBER FLEA BEETLES, EPITRIX TUBERIS GENTNER (COLEOPTERA: CHRYSOMELIDAE), IN POTATO FIELDS." Canadian Entomologist 123, no. 1 (February 1991): 239–40. http://dx.doi.org/10.4039/ent123239-1.

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Early season infestations of adult tuber flea beetles, Epitrix tuberis Gentner, usually are concentrated at the edges of potato fields, and it generally has been assumed that they move into potato fields from the outside inward. This edge-effect suggests that tuber flea beetles overwinter outside potato fields, and other species of flea beetles have been reported to behave similarly (Wolfenbarger 1940; Dominick 1971; Burgess 1981). This may not be true of E. tuberis, however. Hoerner and Gillette (1928), in Colorado, noted that potatoinfesting flea beetles [probably E. cucurneris (Harris), E. subcrinata (Lec.), or E. tuberis] often congregated under piles of old potato vines in potato fields, and Hill and Tate (1942) observed flea beetles feeding on cull tubers in a potato field after harvest. These observations suggest, but do not confirm, that some flea beetles including E. tuberis may remain in harvested potato fields during winter.
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4

Miller, J. S., T. F. Cummings, L. J. Mikitzel, and D. A. Johnson. "Influence of Timing of Harvest in Relation to Haulm Killing and Planting Date on Potato Tuber Rot Caused by Phytophthora infestans." Plant Disease 86, no. 3 (March 2002): 264–68. http://dx.doi.org/10.1094/pdis.2002.86.3.264.

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Killing potato haulms 2 to 3 weeks prior to harvesting tubers is recommended for the management of potato late blight to eliminate the foliage as a source of tuber blight inoculum. Some potato growers in the Columbia Basin of Washington and Oregon, however, harvest tubers within days of killing potato haulms or harvest tubers without killing potato haulms. The susceptibility of potato tubers harvested from green haulms to late blight is unknown. From 1996 to 1998, Russet Burbank and Ranger Russet seed tuber pieces were planted on three different dates and then harvested simultaneously to obtain daughter tubers at different levels of maturity as determined by physiological degree day (P-day) accumulation. Tubers from two trials in 1996 were harvested within 1 to 4 days of haulm killing, tubers from a single trial in 1997 were harvested 16 days after haulm killing, and tubers from two trials in 1998 were harvested 1 and 21 days after haulm killing. Tubers from each plot were divided into two samples; one sample was inoculated the day after harvest and the other sample was inoculated 6 months after harvest on the buds and periderm tissue with a US-8 isolate of Phytophthora infestans. Severity of tuber blight on tuber surfaces and internal tuber tissue was highly correlated. When tubers were harvested within 1 to 4 days after haulm kill, the youngest tubers had the highest percentage of skinning and the lowest percentage of tuber blight. These tests, however, were not designed to test the hypothesis that increased tuber skinning resulted in increased tuber rot. Severity of tuber blight was greater for Ranger Russet tubers than for Russet Burbank tubers. The correlation between the severity of tuber blight at harvest and after 6 months in storage was significant. In some cases, differences in susceptibility to tuber blight due to planting date were observed after 6 months in storage. When tubers were harvested within 1 to 4 days after vine killing, tubers from plants that had been growing longer were more susceptible to late blight tuber rot than tubers from plants that had been growing for a shorter period of time.
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5

TAYE, MULUGETA, W. J. M. LOMMEN, and P. C. STRUIK. "Effects of breaking seed tubers on yield components of the tuber crop Plectranthus edulis." Journal of Agricultural Science 151, no. 3 (May 15, 2012): 368–80. http://dx.doi.org/10.1017/s002185961200041x.

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SUMMARYPlectranthus edulis is an ancient tuber crop, cultivated in Ethiopia, which produces stem tubers on stolons below the ground; however, agronomic and physiological information on this crop is scarce. Three field experiments were carried out at each of two locations (Awassa and Wondogenet, Ethiopia). Expt 1 dealt with the effects of breaking a seed tuber into different numbers of seed pieces before planting, Expt 2 assessed the effect of the weight of the seed tuber piece and Expt 3 investigated the effect of planting different numbers of seed pieces per planting hole. Cultivar Lofuwa was planted in Awassa, whereas cvar Chankua was planted in Wondogenet. Breaking seed tubers in Expt 1 resulted in more main stems/hill, more tubers and smaller individual tubers. In Wondogenet, the tuber yield also increased. Breaking did not affect the number of stolons/m2. Expt 2 indicated that when only one seed piece was planted per planting hole, smaller seed pieces gave fewer stems, fewer stolons and fewer tubers/m2, smaller tubers and lower tuber yields. Expt 3 showed that planting more seed pieces/planting hole gave more stems, more stolons and more tubers/m2, thus increasing tuber fresh yield/m2, whereas the mean tuber weight was not consistently affected. Across all experiments, the tuber yield increased when the number of main stems increased up to three main stems/m2. Higher tuber yields resulting from experimental treatments were either achieved by an effect on number of tubers alone or by combined effects on number of tubers and mean tuber weight, but not by an effect on mean tuber weight alone. The number of small tubers was high in all experiments. Breaking a seed tuber into two or three pieces before planting them in one planting hole consistently resulted in increased numbers of main stems and tuber yield.
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6

Nyankanga, Richard O., Ocen Modesto Olanya, Hans C. Wien, Ramzy El-Bedewy, John Karinga, and Peter S. Ojiambo. "Development of Tuber Blight (Phytophthora infestans) on Potato Cultivars Based on In Vitro Assays and Field Evaluations." HortScience 43, no. 5 (August 2008): 1501–8. http://dx.doi.org/10.21273/hortsci.43.5.1501.

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Tuber blight may result from infection of wounded or unwounded potato tubers exposed to sporangia from foliar blight, soil, or blighted tubers. However, there are limited data on the prediction of tuber blight in field or storage environment based on in vitro assays. To assess this relationship, potato cultivars with foliar blight resistance (R-genes) and general resistance were evaluated for tuber blight incited by Phytophthora infestans (US-1) based on wound-induced and unwounded tuber inoculations. Surface lesion diameter, lesion depth, and frequency distribution of blighted tubers were assessed in in vitro assays and tuber blight incidence determined in field experiments. Significant differences (P < 0.05) in lesion diameter and depth were recorded among cultivars. Surface lesion diameter, depth, and index ranged from 5 to 40, 2 to 16.3, and 15 to 656 mm, respectively, in wound-inoculated tubers. In nonwounded tuber assays, the incidence of blighted tubers ranged from 0% to 8.7% in both years. Tuber blight infection of potato cultivars varied between years in field studies. Although tuber infection differed among cultivars, the frequency of blighted tubers had a normal statistical distribution irrespective of R-genes, implying that foliar resistance may have limited effect on tuber blight occurrence based on in vitro experiments. Prediction of tuber blight based on inoculation assays can be effectively used to estimate and manage blight development in storage environments.
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7

Wurr, D. C. E., J. R. Fellows, R. A. Sutherland, and E. J. Allen. "Determination of optimum tuber planting density for production of tubers in processing ware grades in the potato variety Record." Journal of Agricultural Science 114, no. 1 (January 1990): 11–18. http://dx.doi.org/10.1017/s0021859600070945.

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SUMMARYA series of experiments examining the influences of size and spacing of planted potato tubers (‘seed’ tubers) on tuber yields was conducted at four sites in the UK in 1982–84. A new approach to data analysis was used to estimate the optimum tuber planting density for different ware grades. The optimum density, which maximized returns, decreased with increasing seed tuber weight and ratio of seed-tuber cost to ware value and with lower than average total tuber yields. Changing the required ware grade from 40–65 mm to 40–80 mm had a minimal effect on the optimum tuber planting density.Optimum tuber planting densities were lower than in published recommendations but this disparity appeared to be accounted for by differences in the number of stems produced by each planted tuber. There was some evidence that, with lower seed-tuber weights, the optimum planting density differed with site and that at optimum economic densities small and medium seed tubers outyielded large seed tubers.
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8

Whitfield, A. E., L. R. Campbell, J. L. Sherwood, and D. E. Ullman. "Tissue Blot Immunoassay for Detection of Tomato spotted wilt virus in Ranunculus asiaticus and Other Ornamentals." Plant Disease 87, no. 6 (June 2003): 618–22. http://dx.doi.org/10.1094/pdis.2003.87.6.618.

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A tissue blot immunoassay (TBIA) was developed to detect Tomato spotted wilt virus (TSWV) in Ranunculus asiaticus tubers and other ornamentals. TBIA was comparable to double-antibody sandwich enzyme-linked immunosorbent assay for accuracy and reliability. A nondestructive sampling method was used with R. asiaticus tubers to determine: (i) the relationship between tuber infection and size; (ii) the distribution of TSWV in tubers; and (iii) the relationship between tuber infection and tuber germination. Small tubers had a higher percentage (44%) of infection than large tubers (19%). When destructive sampling was acceptable, the central stem tissue was the most reliable to test. TSWV infection was associated with a significant reduction of tuber germination. Among the tubers that tested positive for TSWV infection, 48% of those that germinated produced foliage in which TSWV was detected. The remaining 52% of the infected tubers planted that germinated developed into plants that were asymptomatic and in which TSWV was not detectable after germination. Only 4% of tubers that tested negative produced infected plants after germination. Our results indicate that TBIA can be used in TSWV management programs to identify infected plants and to index tuber crops.
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9

Sattar, M. A., N. Sultana, M. M. Hossain, M. H. Rashid, and A. K. M. Aminul Islam. "GENETIC VARIABILITY, CORRELATION AND PATH ANALYSIS IN POTATO (Solanum tuberosum L.)." Bangladesh Journal of Plant Breeding and Genetics 20, no. 1 (June 30, 2007): 33–38. http://dx.doi.org/10.3329/bjpbg.v20i1.17023.

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Genotypic and phenotypic variability, heritability, genetic advance, correlation coefficients and path coefficients analysis were done for yield and its contributing characters in 28 genotypes of potato. High heritability coupled with high genetic advance as percent of mean and high genotypic coefficients of variation were observed for number of tubers per plant, yield per plant and average weight of a tuber suggesting selection for these traits would give good response. Genotypic and phenotypic correlation of the number of tubers per plant and weight of tubers per plant were highly significant. Plant vigour, number of compound leaves per plant and number of tubers per plant, average weight of a tuber and dry matter content of tuber had high degree of positive association with tuber yield per plant. As per path analysis, average weight of tuber and total number of tubers per plant contributed maximum direct effect to tuber yield indicating their importance as selection index for yield improvement.DOI: http://dx.doi.org/10.3329/bjpbg.v20i1.17023
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10

Levin, Aaron, Alexander Baider, Evgenia Rubin, Ulrich Gisi, and Yigal Cohen. "Oospore Formation by Phytophthora infestans in Potato Tubers." Phytopathology® 91, no. 6 (June 2001): 579–85. http://dx.doi.org/10.1094/phyto.2001.91.6.579.

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The ability of Phytophthora infestans, the causal agent of potato and tomato late blight, to produce oospores in potato tuber tissue was studied in the field and under laboratory conditions. In 1998 and 2000 field experiments, the canopy of potato cvs. Alpha and Mondial, respectively, were coinoculated with A1 + A2 sporangia of the fungus, and the infected tubers collected at harvest were examined for the presence of oospores. In 1998, only 2 of 90 infected tubers had oospores, whereas none of the 90 tubers examined in 2000 had any oospores. In the latter experiment, infected tubers kept in storage up to 12 weeks after harvest had no oospores. Artificial co-inoculations of whole tubers with A1 + A2 sporangia resulted only rarely in the formation of oospores inside the tubers. Co-inoculations of potato tuber discs taken from dormant tubers 0 to 16 weeks after harvest failed to support any oospore production, whereas discs taken from sprouting tubers of ≥18 weeks after harvest allowed oospores to form. Tuber discs showed enhanced oospore formation when treated before inoculation with either sugars, amino acids, casein hydrolysate, β-sitosterol, or chloroethylphosphonic acid. In contrast, reducing airflow into the petri dishes where potato tuber discs were incubated reduced the number of oospores produced. The number of oospores produced in tuber tissue was lower compared with that in leaf tissue regardless of the origin of isolates used. The data show that the ability of Phytophthora infestans to produce oospores in potato tuber tissue is very limited and increases with tuber aging.
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11

Porter, L. D., T. F. Cummings, and D. A. Johnson. "Effects of Soil-Applied Late Blight Foliar Fungicides on Infection of Potato Tubers by Phytophthora infestans." Plant Disease 90, no. 7 (July 2006): 964–68. http://dx.doi.org/10.1094/pd-90-0964.

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Potato tuber infection was assessed under greenhouse and outdoor conditions when late blight foliar fungicides were applied to soil 24 h prior to soil infestation with a suspension of zoospores and sporangia of Phytophthora infestans. Spore viability of P. infestans in soil treated with various fungicides was determined using buried healthy whole tubers and by assaying infested soil applied to freshly cut tuber disks. Protection of tubers and tuber disks from infection was more effective when soil was treated with mancozeb, metiram, and cyazofamid than with other fungicides. Whole tuber infections were significantly less in soils treated with mancozeb, metiram, fluazinam, and fenamidone than when treated with distilled water. Infection of buried tubers and tuber disks was prevented for 3 to 5 days following a single soil application of mancozeb or metiram under outdoor conditions. The tuber disk method was more sensitive in determining the efficacy of a fungicide in inhibiting infection and spore viability than using whole buried tubers. However, both methods of determining viability may determine different modes of action of some fungicides that inhibit infection since whole tubers were not infected when protected by some fungicides but tuber disks were infected.
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12

Benz, J. S., E. R. Keller, and D. J. Midmore. "Planting materials for warm tropic potato production: production and field performance of nursery-produced tubers." Journal of Agricultural Science 127, no. 1 (August 1996): 67–81. http://dx.doi.org/10.1017/s0021859600077388.

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SUMMARYPotato production in the lowland tropics is constrained by lack of affordable supplies of planting material. Therefore, the potential to produce in situ tuber seed from true potato seed (TPS) seedlings and rooted stem cuttings under nursery conditions in the warm tropics was studied, and their yields were compared with those of the same materials obtained under cool conditions. Subsequently, their field performance in the warm tropics was evaluated.Tuber yield from TPS seedlings and rooted cuttings transplanted in nursery beds under warm conditions ranged from 50% to < 20% of that obtained in cool conditions, but reductions in tuber numbers were less marked under warm conditions. Survival of seedlings was less than that of stem cuttings, but tuber numbers of seedlings exceeded those of rooted cuttings by a factor of two or more (e.g. 700 m−2 for seedlings v. 224 m−2 for rooted cuttings). Low tuber number is physiologically inherent in cuttings, as is high tuber number in seedlings. Total tuber yields varied significantly amongst clones grown in the warm climate from rooted cuttings, not always in proportion to the number of tubers produced. Differences in tuber yield and tuber number were less marked between the two TPS progenies studied.The field comparisons highlighted the 30–40% lower yield potential for warm-climate-produced nursery seed materials. Slower emergence and fewer stems apparently were in part responsible for this effect; however, neither tuber number harvested nor the proportion of marketable tubers was affected by site of production of seed materials. Cutting medium-sized warm-produced tubers (mean 23 g), the use of larger sized whole tubers (10–20 g v. 5–10 g) or increasing the planting density of 5 g tubers from 8·8 to 15·5 plants m-2 significantly increased yields by 4·9, 2·25 and 3·5 t ha-1, respectively, but yields were not increased further by 20–40 g tubers nor by 22·2 plants m-2. Small seedling tubers (≤ 5 g) can potentially lead to high stem numbers per unit weight of tubers, but their success in plant establishment was hampered in warm climates, especially in the presence of soil pathogens. Cool-climate-produced seedling tubers and tubers from cuttings can compete physiologically with field-produced seed tubers when used as planting materials in the warm tropics. However, with few exceptions, no crop from tubers produced under warm conditions could match the performance of crops from similar cool-produced tubers when planted out in the warm tropics.
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13

Porter, L. D., N. Dasgupta, and D. A. Johnson. "Effects of Tuber Depth and Soil Moisture on Infection of Potato Tubers in Soil by Phytophthora infestans." Plant Disease 89, no. 2 (February 2005): 146–52. http://dx.doi.org/10.1094/pd-89-0146.

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The effects of tuber depth, soil type, and soil moisture on potato tuber infection due to Phytophthora infestans were assessed under greenhouse conditions in soil contained in large pots. Healthy tubers were used to assess infection and were either hand buried in soil at specific depths or naturally formed from potato plants growing in the soil. A spore suspension of P. infestans was chilled to induce zoospore formation and a suspension of resulting zoospores and sporangia were applied to the soil. Soil depth at which tubers became infected was used to determine the extent of spore movement in the soils. Tuber infection significantly decreased with increasing soil depth. Most infected tubers were found at the surface of soil; infection was rare on tubers at 5 cm or deeper in the soil. Amount of tuber infection varied among soil types. Significantly less tuber infection occurred in a Shano silt loam than in medium and fine sands. Only tubers on the soil surface were infected in the Shano silt loam. Depth in soil at which tubers became infected did not differ significantly among Quincy fine sand, Quincy loamy fine sand, and Quincy medium sand. Increased soil moisture did not significantly increase the soil depth at which tuber infection occurred, regardless of the soil type.
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Durant, Daphné, Laurent Desnouhes, Matthieu Guillemain, Hervé Fritz, and François Mesléard. "How do shoot clipping and tuber harvesting combine to affectBolboschoenus maritimusrecovery capacities?" Botany 87, no. 9 (September 2009): 883–87. http://dx.doi.org/10.1139/b09-050.

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In French Mediterranean wetlands, the combined effects of predation of tubers by wildlife and grazing of aboveground tissue by livestock on the recovery capacities of Bolboschoenus maritimus (L.) Palla are not well known. A container study was conducted that applied tuber harvests at varying levels (20%–90%) and shoot clipping (with or without). Response to harvesting and clipping was recorded as changes in total biomass, number, and mean mass of tubers (calculation of variation indexes). Bolboschoenus maritimus failed to recover from even the lowest tuber harvesting level of 20% and the total number of tubers and biomass decreased. A significant decrease in mean tuber mass over time and approximately no production of new tubers accounted for this absence of compensatory response. The harvesting level had a linear effect on the variation indices of total number of tubers and mean tuber mass. By separating the relative effect of shoot clipping from that of tuber harvesting alone, the results showed that clipping had an additive effect on mean tuber mass, reducing it by about 20%, without any effect on tuber number. The absence of compensatory response under our experimental conditions suggests that clonal plant regrowth partially depends on post-disturbance environmental conditions in the growing season, in our case, dry conditions.
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Karan, Yasin Bedrettin. "The impact of haulm killing on yield and quality of potato (Solanum tuberosum L.)." PLOS ONE 16, no. 8 (August 5, 2021): e0255536. http://dx.doi.org/10.1371/journal.pone.0255536.

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Disease-free and superior quality seed tubers could be obtained by haulm (vine) killing, which also reduces weight loss during storage. Higher resistance during storage ensures that seed tubers will be at the desired physiological age at the time of planting. The use of healthy seed tubers of appropriate physiological age will have positive impact on yield and quality. This study aimed to investigate the effects of haulm killing on seed potato yield and yield components (total tuber yield, average tuber yield/plant, number of tubers and average tuber weight) under semi-arid climate of Artova district in Tokat province, Turkey. The field studies were carried out during potato growing seasons of 2017 and 2018. The experiment consisted of two factors, i.e., potato cultivars and haulm killing. Five different potato cultivars, i.e., ‘Agria’, ‘Marabel’, ‘Hermes’, ‘Marfona’ and Madeleine were included in the study. The haulm killing treatments were ‘haulm killing’ and ‘no haulm killing’. Haulm killing positively affected the number of tubers per plant and average tuber weight, which are directly related to the tuber yield. Tuber seed yield in the first and second year with haulm killing treatment was 40.78 and 44.05 tons/ha, respectively. The yield without haulm killing in the first and second years was 37.78 and 38.76 tons/ha, respectively. The dry matter ratio of tubers with haulm killing was 21.89% in 2017 and 22.35% during 2018. The dry matter ratio of tubers without haulm killing was 20.57% in 2016 and 21.03% during 2017. The results revealed haulm killing had positive impact on yield, yield-related parameters and dry matter content of seed tubers. Therefore, haulm killing is recommended for higher yield and better quality of seed tubers.
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Budiman Manurung, Siti Zahrah, and Zulkifli. "PEMBERIAN HORMAX DAN NPK MUTIARA 16:16:16 PADA TANAMAN UBI JALAR ( Ipomoea batatas L.)." DINAMIKA PERTANIAN 34, no. 2 (August 6, 2020): 139–50. http://dx.doi.org/10.25299/dp.2018.vol34(2).5423.

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ABSTRACT The purpose of this study was to determine the effect of Hormax and NPK Mutiara (16:16:16) on sweet potato plants. The design used in this study was a Factorial Complete Randomized Design consisting of two factors. The first factor is Hormax (H) at doses of 0, 1, 3, and 5 ml per liter of water while the second factor is NPK Mutiara (16:16:16) (N) with concentrations of 0, 3.15, 6.3, and 9.45g per plant. The parameters observed were the number of crop tubers (tubers), tuber weight per plot (g), tuber weight per tuber (g), tuber weight per plant (g), wet pruned weight (g), harvest index. The last observation data were analyzed statistically and continued with a BNJ follow-up test at the 5% level. The results showed that the interaction of giving Hormax and NPK Mutiara (16:16:16) significantly affected the number of tubers per plant, tuber weight per plot, tuber weight per fruit, weight. The best treatment is in the combination of H2N2 fertilizer concentration of 3 ml/liter of water and 6.3 g / plant. The main influence of hormax is evident on the parameters of the number of tubers per plant, tuber weight per plot, tuber weight per tuber, tuber weight per plant, wet perched weight, harvest index, the best treatment of 3 ml per liter of water (H2). The main effect of NPK Mutiara fertilizer (16:16:16) is real on the parameters of the number of tubers per plant, tuber weight per plot, tuber weight per fruit, tuber weight per plant, wet perched weight, harvest index, best treatment ie 6.3 g per plants (N2). Keywords: Hormax, NPK, Sweet Potatoes
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17

Knowles, N. Richard, and Gabor I. Botar. "Effect of altering the physiological age of potato seed-tubers in the fall on subsequent production in a short-season environment." Canadian Journal of Plant Science 72, no. 1 (January 1, 1992): 275–87. http://dx.doi.org/10.4141/cjps92-033.

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The efficacy of utilizing "controlled seed-tuber aging" as a technique to enhance yield and improve tuber quality in areas with relatively short growing seasons was investigated in a 3-yr study. Prior to planting in the field, five physiological ages of Russet Burbank, Carlton, Norchip and Superior seed-tubers were produced by varying the heat-unit accumulation over a 200-d storage interval. Total yield increases of up to 90% and substantial improvements in tuber grade were achieved by planting aged (600–900 degree-day (dd)) seed-tubers. Plant growth from aged Russet Burbank seed-tubers was modelled to identify the mechanisms by which yield and quality were altered. Growth analysis demonstrated that the age-induced yield increases were due to faster emergence, faster leaf-area establishment, and tuberization earlier in the growing season compared with that from younger seed-tubers. The annual life cycle was thus accelerated, allowing plants from older seed-tubers to utilize the short (120-d) growing season more efficiently than those from younger seed-tubers. This was reflected in a higher harvest index: plants from 739 dd seed-tubers partitioned 63% of their total fresh weight into tubers compared with 48% for those from 66 dd seed-tubers (based on the quadratic model describing the relationship between seed-tuber age and and harvest index at 121 d after planting). The technique appears to be very promising for enhancing yield and/or promoting ’earliness’ of potatoes in regions with short growing seasons.Key words: Solanum tuberosum, seed-tuber age, plant growth, yield
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18

Swisher Grimm, Kylie D., Tariq Mustafa, W. Rodney Cooper, and Joseph E. Munyaneza. "Growth and Yield Performance of Solanum tuberosum Grown from Seed Potatoes Infected with ‘Candidatus Liberibacter solanacearum’ Haplotypes A and B." Plant Disease 104, no. 3 (March 2020): 688–93. http://dx.doi.org/10.1094/pdis-05-19-1125-re.

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Zebra chip (ZC) disease of potato (Solanum tuberosum) is associated with infection by ‘Candidatus Liberibacter solanacearum’ (Lso). Two haplotypes of Lso—A and B—occur in the United States. Lso haplotype B is more virulent than haplotype A, causing greater disease incidence in tubers, more severe symptoms, and greater loss in tuber yield. This study assessed whether tubers from infected plants generate new infected plants the following year. The effects of both Lso haplotypes A and B on tuber resprout were examined on five potato cultivars. When compared with noninfected tubers, overall plant emergence rate from Lso A- or B-infected tubers was lower, plants emerged slower, and plants generated lower daughter tuber yields in weight and quantity. Plants generally emerged poorly from Lso B-infected tubers and produced lower daughter tuber yields than Lso A-infected tubers. Regardless of Lso treatment, all daughter tubers were asymptomatic, and only 0.3% tested positive for Lso in experiments conducted over 2 years. This suggests that plants generated from Lso A- and Lso B-infected seed potatoes with severe ZC symptoms are likely not a significant source of Lso in potato fields.
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19

El-Amin, S. M., B. Adam, E. Varis, and E. Pehu. "Production of Seedling Tubers Derived from True Potato Seed and Their Use as Seed Tubers in the Sudan." Experimental Agriculture 32, no. 4 (October 1996): 419–26. http://dx.doi.org/10.1017/s0014479700001502.

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SUMMARYSeedling tubers of three true potato seed (TPS) crosses raised in a seedbed soil mixture of clay, sand and dry leaves produced about 3.1 kg of seedling tubers m−2 in the growing season of 1988–89 and between 4.3 and 5.1 kg m−2 in 1989/90. The seedling tubers produced were stored and their use as seed tubers was subsequently compared with the locally popular variety Alpha. The mean tuber yields of the hybrids ranged between 9.4 and 11 t ha−1 in 1990/91 and between 21.9 and 22.9 t ha−1 in 1991/92. Mean tuber yields of cultivar Alpha were 14.3 t ha−1 in 1990/91 and 24.1 t ha−1 in 1991/92, showing that tuber yields comparable to those of imported seed tubers could be obtained from seedling tubers of TPS origin.
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20

El-Amin, S. M., B. Adam, E. Varis, and E. Pehu. "Production of Seedling Tubers Derived from True Potato Seed and Their Use as Seed Tubers in the Sudan." Experimental Agriculture 32, no. 4 (October 1996): 419–26. http://dx.doi.org/10.1017/s0014479700003781.

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SUMMARYSeedling tubers of three true potato seed (TPS) crosses raised in a seedbed soil mixture of clay, sand and dry leaves produced about 3.1 kg of seedling tubers m−2 in the growing season of 1988–89 and between 4.3 and 5.1 kg m−2 in 1989/90. The seedling tubers produced were stored and their use as seed tubers was subsequently compared with the locally popular variety Alpha. The mean tuber yields of the hybrids ranged between 9.4 and 11 t ha−1 in 1990/91 and between 21.9 and 22.9 t ha−1 in 1991/92. Mean tuber yields of cultivar Alpha were 14.3 t ha−1 in 1990/91 and 24.1 t ha−1 in 1991/92, showing that tuber yields comparable to those of imported seed tubers could be obtained from seedling tubers of TPS origin.
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21

Hussain, Ibrar, and Noor Ul Amin. "Caladium cv. Florida sweetheart production at different planting depths and sowing dates." Ornamental Horticulture 24, no. 4 (October 30, 2018): 311–16. http://dx.doi.org/10.14295/oh.v24i4.1194.

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Ornamental bulbous crops emergence and yield can be improved by its emergence from soil. The response of Caladium to different planting depths and dates was investigated at Ornamental Horticulture Nursery, Department of Horticulture, The University of Agriculture, Peshawar during the year 2008. Randomized Complete Block Design in a split plot arrangement was used repeated three times. Sowing dates (30th March, 15th April and 30th April) were allotted to main plots whereas planting depths (2.5 cm, 5 cm, 7.5 cm and 10 cm) were kept in sub plots. Findings revealed that Caladium tubers sown on 30th March took maximum days to sprouting (33), produced maximum number of sprouts plant-1 (2.21), gained maximum tuber size (40.88 cm3) with high tuber yield (5397 kg ha-1). On the other hand, tubers sown on 30th April took less days to sprouting (20.21), produced less number of sprouts plant-1(1.53), produced small tuber (33.28 cm3) and total tuber yields was also less (4374 kg ha-1). In case of planting depth, Caladium tubers sown at a depth of 7.5cm resulted in maximum plant height (52 cm), tuber size (41.76 cm3), and tuber yield (5288 kg ha-1) while maximum number of tubers plant-1 (1.92) was observed at a depth of 10 cm. Tubers sown in 2.5 cm depth resulted in minimum tuber yield (4538 kg ha-1) and plant height (46.56 cm). To maximize vegetative as well as tubers production of Caladium cv. Florida sweet heart, it shall be sown on 30th March with 7.5cm depth.
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22

Khatri, Bhim Bahadur, R. S. Tegg, Philip H. Brown, and C. R. Wilson. "Determining Specific Window Period for Common Scab Disease Infection in Potato Tubers." Journal of Nepal Agricultural Research Council 3 (May 8, 2017): 19–26. http://dx.doi.org/10.3126/jnarc.v3i1.17271.

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A series of experiments was conducted under glasshouse and hydroponic conditions to determine the specific window period for common scab disease infection in potato tubers. The study was performed in a glasshouse system where separate tubers from the root zone were inoculated at different intervals during plant growth along with a novel hydroponic system to inoculate individual tubers at specific times of development growth allowing non-destructive observations of common scab symptoms developing. The window of tuber susceptibility to common scab disease infection was shown to vary with the season or conditions under which the plants were grown. Different internodes on tubers were found susceptible to infection at different times during tuber development. Basal internodes, which are the first sections of the tuber to expand, were susceptible to infection in the beginning of tuber development, whereas apical internodes only became susceptible later in tuber growth when the basal internodes were no longer susceptible.Journal of Nepal Agricultural Research Council Vol.3 2017: 19-26
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23

Kołodziejczyk, Marek. "Phenotypic variation of yielding of medium-early cultivars of edible potato." Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin, no. 294 (April 26, 2021): 27–33. http://dx.doi.org/10.37317/biul-2021-0003.

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The aim of the study was to analyse the genotypic and environmental variation in yield, as well as the structure of the yield of tubers of medium-early cultivars of edible potato. The field study was carried out in the years 2015-2019 at the experimental station in Prusy near Krakow (50o07ʼN, 20o05ʼE) on chernozem. The following five potato cultivars were evaluated: Finezja, Oberon, Laskara, Satina and Tajfun. The total and commercial yield of tubers, the average tuber mass, the quantity of tubers from a plant, as well as the share of the fraction of large, commercial and small tubers were determined in the study. Of the potato features that were evaluated, the share of the commercial tuber fraction was the most stable. A low diversity was also found in the case of total and commercial yield of tubers, whereas the share of the fraction of small tubers was the least stable feature. The size of yields and their structure were determined mostly by environmental factors. Only in the case of the share of fractions of large and small tubers were the varietal properties more decisive than the genotypic-environmental interaction. The conducted cluster analysis identified two groups of cultivars: first—with a high yielding potential, substantial average tuber mass, a substantial share of commercial and large tubers; and second—with significantly lower tuber mass, substantial quantity of set tubers, particularly the fine ones with a simultaneous small share of large tubers.
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24

Zulu, D., R. H. Ellis, and A. Culham. "Propagation of lusala (Dioscorea hirtiflora), a wild yam, for in situ and ex situ conservation and potential domestication." Experimental Agriculture 56, no. 3 (May 19, 2020): 453–68. http://dx.doi.org/10.1017/s0014479720000083.

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SummaryLusala (Dioscorea hirtiflora Benth. subsp. pedicellata Milne-Redh) is an important wild edible tuber foraged widely from natural forests in Southern Zambia, but at risk from overharvesting and deforestation. Its propagation was investigated in glasshouse studies to explore potential domestication and future in situ and ex situ genetic resources conservation. Almost all tubers planted with visible shoot buds produced vines, with no effect of tuber size on vine emergence or tuber yield. Few tubers without visible shoot buds at planting produced vines, but those that did not re-tuberized. The progeny provided good vine emergence and similar tuber yield, with vines from tubers produced by re-tuberization being more vigorous. Re-tuberization in the absence of vine emergence also occurred in other experiments. Minisetts cut from the proximal end of tubers provided better vine emergence (with more from 20-mm than 10-mm-long sections) and greater tuber yield than mid- or distal minisetts. Nodal stem cuttings rooted well, vined, and provided small tubers. This study shows that lusala can be propagated successfully from tubers, minisetts, nodal vine cuttings, or mini-tubers from nodal vine cuttings, for genetic resources conservation and/or domestication. Domestication is likely to be hampered by the long period required for vines to emerge and establish. More sustainable foraging, including re-planting in natural forests, is recommended to balance consumption of lusala in the region and promote its long-term conservation.
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25

FABUNMI, Thomas O., and Joyce U. AMALAHU. "Tuber Depth and Yield Response of Tiger Nut (Cyperus esculentus) to Soil Texture and Rates of Poultry and Pig Manure." Notulae Scientia Biologicae 11, no. 2 (June 28, 2019): 283–90. http://dx.doi.org/10.15835/nsb11210426.

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A pot experiment was conducted to evaluate tuber depth and weight of tiger nut produced in loamy fine sand and sandy clay soil using 0, 200, 300 or 400 g per pot of poultry or pig manure in a 2 × 2 × 4 factorial experiment arranged in completely randomized design and replicated three times. Total tuber weight and weight of tubers at 10 cm were significantly increased by application of manure compared with the control. Significant interaction of soil texture X manure types X manure rates was recorded on weight of tubers at 20 cm. Percentage of tubers at 0-10 cm was 90.6-92.1% (91.5-93.6% tuber weight); while 6.68-8.96% of the tubers (5.49-8.47% tuber weight) were harvested between 10-20 cm soil depth; only 0-0.94% of the tuber weight was harvested beyond 20 cm depth. Pig manure had positive effect on tiger nut productivity on loamy fine sand and sandy clay soil, while with poultry manure tiger nut productivity was enhanced on sandy clay soil; 300 g of pig or poultry manure produced similar weight of tiger nut tubers and is considered optimum for tiger nut productivity. Sandy clay and loamy fine sand had similar effect on depth and yield of tiger nut. More than 99% of the tubers were confined to 0-20 cm soil depth. Information on how deep the tubers of tiger nut can grow in soil of different texture and fertility status will enhance precise harvesting.
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26

Neilson, Jonathan A. D., Anne M. Smith, Lilia Mesina, Rachel Vivian, Susan Smienk, and David De Koyer. "Potato Tuber Shape Phenotyping Using RGB Imaging." Agronomy 11, no. 9 (September 6, 2021): 1781. http://dx.doi.org/10.3390/agronomy11091781.

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Potato tuber shape is an important quality trait for breeding and variety development. Length to width (L/W) ratio is a commonly used method to score potato tubers for suitability for different markets and is relatively easy to measure, though labor intensive when done manually. L/W also does not adequately capture secondary growth and other tuber malformations that contribute to tuber shape. Tuber shape has a genetic component and is a prime target for early breeding selection. In the current study we developed an image analysis pipeline to extract tuber shape statistics from images taken using inexpensive, commercially available cameras. The image processing pipeline was used to evaluate greenhouse grown tubers from 32 unique crosses. Tubers from greenhouse grown plants were then grown in a field located in Vauxhall, AB, Canada, and evaluated for tuber shape. Randomly selected tuber images were also shown to industry agronomists and potato growers located in Southern Alberta and their shape scored for suitability for processing (French fry and chipping) markets. Based on measurements taken from greenhouse grown tubers we were able to classify whether mean tuber shape from field grown plants were within ideal shape parameters for processing markets with ~76–86% accuracy. Based on performance of progeny we identified parents which show higher breeding value for tuber shape.
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27

He, Wei, Jin Li, Min Pu, Zhi-Gang Xu, and Lijun Gan. "Response of photosynthate distribution in potato plants to different LED spectra." Functional Plant Biology 47, no. 12 (2020): 1128. http://dx.doi.org/10.1071/fp20131.

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Although light is essential to photosynthesis, few studies have examined the effects of different LED spectra on photosynthate distribution in potato plants. Therefore, we exposed tuberising potato plants to white (W), red (R), blue (B) and green (G) LED treatments and compared tuber development and carbohydrate partitioning among the plants. R-treated plants had greater photosynthetic leaf area during tuber development compared with those under other treatments, thus enhancing assimilation. Although R-treated plants had higher 13C assimilation in the leaves, stems and roots than those under B treatment, there was no difference in partitioning of 13C assimilation and yield in the tubers of each plant between R and B treatments. For the tuber size, R-treated plants had a higher ratio of large tubers (&gt;20 g) and a lower ratio of small (2–20 g) and medium-sized (10–20 g) tubers than those under W. B-treated plants had more medium-sized and large tubers than those under W. The reason may be that plants under R treatment distributed more assimilated 13C in their first tuber than those under other treatments. By contrast, plants under B balanced photosynthate distribution among their tubers. Leaves under G treatment had lower photosynthetic efficiency and ΦPSII than those under W, R or B treatment, which resulted in lower 13C photosynthate allocation in organs and lower tuber yield per plant than in R and B treatments. Overall, R treatment promoted 13C assimilation and led to more large tubers than other treatments. B-treated plants distributed more photosynthates into tubers rather than other organs and showed balanced tuber development.
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28

Skalický, J. "Research of sugar-beet tubers mechanical properties." Research in Agricultural Engineering 49, No. 3 (February 8, 2012): 80–84. http://dx.doi.org/10.17221/4956-rae.

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Approach to the problems of sugar-beet tubers surface damage dependence on harvesting technology. Investigation of sugar-beet tubers damage when falling on wood and iron surfaces and in the next case tuber damage caused by their fall on the tuber heap. Research of damage rate dependence on the fall height. Evaluation of damage rate was carried by the I.I.R.B. method (method used by all sugar-beet growing countries of Western Europe). The results refer that no considerable differences in damage rate after the fall on the wood or iron bottoms have been ascertained. The height of 1.5 m can be considered in all cases as the limit value of the tubers fall, when share of heavily damaged tubers reached acceptable values of 10&ndash;15%, but that the share increases significantly at higher falling height. The lifting bodies construction requires also a knowledge of dependence between root depth and force for tuber release from soil in relation to the tuber weight. Medium force needed for tubers lifting ranges from 17 to 27 kp, maximum value 50 kp was found out for tubers of weight above 3 kg.
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29

Niemira, Brendan A., William W. Kirk, and Jeffrey M. Stein. "Screening for Late Blight Susceptibility in Potato Tubers by Digital Analysis of Cut Tuber Surfaces." Plant Disease 83, no. 5 (May 1999): 469–73. http://dx.doi.org/10.1094/pdis.1999.83.5.469.

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A method for quantification of late blight (Phytophthora infestans) in potato tuber tissue using a digital scanner and image analysis software is presented. The average reflective intensity of light reflected from the cut surface of sample tubers measures the darkened, diseased potato tuber tissue amid lighter, late blight-free tissue. In the absence of disease, potato variety, tuber shape, and tuber size do not influence the scan results. While digital quantification of late blight in tubers under controlled inoculation conditions is consistent, the digital assessments of late blight did not correspond exactly with those from a conventional subjective visual method. Used together, the methods can provide complementary information regarding varietal susceptibility to P. infestans development on the tuber surface and internal tuber tissue. The method of image analysis presented may be used to determine susceptibility of potato tubers to late blight in varietal development programs, storage research programs, or other tuber research programs.
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30

Guo, Wen Bin, Chun Guang Wang, and Jing Jing Gao. "Study on Correlation between the Starch Content of Potato Tuber and its Viscoelastic Characteristics." Advanced Materials Research 591-593 (November 2012): 2545–50. http://dx.doi.org/10.4028/www.scientific.net/amr.591-593.2545.

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When potato tubers had received the exogenic action, water and starch in tubers generated tougor pressure which would act on cell walls in the tuber tissue, so starch content and water ratio have an obvious effect on the mechanical characteristics of potato tubers. In order to provide a mechanical method for detecting the starch content of potato tubers, correlation between viscoelastic characteristics and starch content of tubers was studied. In the research, the tubers of Desiree potato were compressed by cylindrical probe, and showed nonlinear stress-strain curves. The viscoelastic model of potato tuber was established, and its viscoelastic parameters were determined. Meanwhlie, the starch content and water ratio of potato tuber were detected after mechanical tests, and the correlation between viscoelastic parameters and starch content was analysed. According to the results of correlation analysis, viscosity coefficient which had been obtained from the viscoelastic model was significantly correlated with starch content and water ratio. Finally, the regression equation of starch content and the viscosity coefficient was determined.
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31

Okeyo, James A., and Ronald D. Morse. "388 EFFECTS OF DEHAULMING ON CANOPY GROWTH AND TUBER YIELD OF `YUKON GOLD'." HortScience 29, no. 5 (May 1994): 486f—486. http://dx.doi.org/10.21273/hortsci.29.5.486f.

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Seed tubers of `Yukon Gold' (Solanum tuberosum L.) exhibit strong apical dominance, resulting in relatively poor stem emergence. Cutting seed tubers to overcome apical dominance in `Yukon Gold' results in irregular, uneven stem emergence. In 1992 and 1993, experiments were conducted to evaluate the effects of dehaulming (excising stems to ground level after field emergence) whole, cross- and longitudinal-cut seed tubers of `Yukon Gold' on canopy growth and tuber yield. For all seed piece types, dehaulming during the first week of field emergence produced uniform plant stands and increased yields of U.S. no. 1 tubers by 16 and 42% and large tubers (> 6.4 cm dia.) by 340 and 64% in 1992 and 1993, respectively. Our data indicate that tuber bulking rate was increased by dehaulming. The possible causes and implications of increased tuber bulking rates in dehaulmed potato plants are discussed.
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32

Lommen, W. J. M., and P. C. Struik. "Influence of a single non-destructive harvest on potato plantlets grown for minituber production." Netherlands Journal of Agricultural Science 40, no. 1 (March 1, 1992): 21–41. http://dx.doi.org/10.18174/njas.v40i1.16527.

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In vitro-propagated potato cv. Ostara and Bintje plantlets were transplanted in a greenhouse at 350 plants/msuperscript 2 under tuber-inducing conditions. Plants growing undisturbed were compared with plants from which tubers >=0.3 g were removed in a single non-destructive harvest 3-8 weeks after transplanting. In undisturbed plants tuber initiation slowed down 4 weeks after transplanting, and an average of 2 tubers/plant (average weight 5 g) were harvested in 11 weeks. After a non-destructive harvest new stolons and tubers were initiated, but overall and tuber growth rates were reduced, probably as a result of the combined effects of tuber removal, root damage and deep replanting. Highest tuber numbers and lowest growth rate reductions occurred when growth was at its maximum. The highest number of tubers/plant (3.44) was achieved with non-destructive harvesting 6 weeks after transplanting, but FW/tuber decreased with delay in harvesting from 1.97 to 0.77 g. Using this non-destructive harvesting procedure >1400 and 2400 minitubers >=0.3 g (average weight 1-2 g) could be produced per msuperscript 2 within 8 and 9 weeks of transplanting by Ostara and Bintje, respectively, and would be suitable for use in large-scale seed tuber production programmes. (Abstract retrieved from CAB Abstracts by CABI’s permission)
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33

Treder, Krzysztof, Włodzimierz Przewodowski, and Agnieszka Barnyk. "Factors influencing detection of Potato Leafroll Virus and Potato Virus Y in potato tuber extracts." Plant Breeding and Seed Science 59, no. 1 (January 1, 2009): 65–74. http://dx.doi.org/10.2478/v10129-009-0005-7.

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Factors influencing detection of Potato Leafroll Virus and Potato Virus Y in potato tuber extracts Detection of Potato leafroll virus (PLRV) and Potato virus Y (PVY) directly in potato tubers has been influenced by several factors. The most important were: the place of tuber sampling, preincubation of tuber sap before loading into wells of microplate and duration of tubers storage after collecting from field. The concentration of both viruses was highest in the heel part of tubers, whenever tested. Preincubation of tuber sap for several hours improved true/false signal ratio for dormant tubers and enabled reliable detection of both viruses. However after natural dormancy breaking it was necessary to change Cocktail-ELISA procedure to obtain reliable results, consistent with DAS-ELISA on leaves. The sap was not preincubated but loaded into wells directly after sample collecting and immuno-enzymatic reaction was developed overnight in refrigerator.
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34

Türkmen, Ayten Kübra, Caner Yavuz, Sarbesh Das Dangol, Cehibe Tarım, Ufuk Demirel, and Mehmet Emin Çalışkan. "Evaluation of Micro Tuberization Performances of Different Genotypes." Turkish Journal of Agriculture - Food Science and Technology 5, no. 4 (April 6, 2017): 353. http://dx.doi.org/10.24925/turjaf.v5i4.353-357.1203.

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Certified potato seed tuber usage is one of the most important steps for production of high yield and quality potatoes. For this reason different seed tuber production methods have been developed. Among these methods, mini tuber production is the most popular one. In order to produce mini tubers, firstly potato plants are produced in vitro, and these plants are transferred to an environmentally-controlled greenhouse. Thus, disease- and virus-free mini tubers are produced as seed tubers. However, in vitro section of mini tuber production creates problems like storage and transfer of in vitro plants, and adaptation period of the plants to greenhouse conditions. In vitro micro tuber (MT) formation has been selected as a solution of these problems. The aim of the study was to produce micro tubers from 15 different genotypes and evaluate their micro tuberization performances to determine the genotype effect on MT formation. 3 varieties, 3 breeding lines and 9 different genotypes from International Potato Center (CIP) were selected for the study. For this purpose, micro tubers are produced in vitro by using Murashige and Skoog (MS) medium supplemented with 8% sucrose and 0.1 mg/L thidiazuron (TDZ). All experiments were conducted under dark conditions and 22/16 °C (8/16 h) temperature cycle. The micro tuberization performances were evaluated according to MT number per plant, MT formation rate (%), MT weight per plant (g), mean MT weight (g), mean MT diameter (mm). Differences between micro tuber production performances of different genotypes were determined and CIP395017.229 was identified as the most promising genotype to produce micro tubers.
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35

Tegg, Robert S., Ross Corkrey, Herdina Herdina, Alan C. McKay, Nigel S. Crump, Rudolf F. de Boer, Tonya J. Wiechel, and Calum R. Wilson. "Modeling Pathogen DNA Content and Visual Disease Assessment in Seed Tubers to Inform Disease in Potato Progeny Root, Stolon, and Tubers." Plant Disease 99, no. 1 (January 2015): 50–57. http://dx.doi.org/10.1094/pdis-04-14-0337-re.

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Measurement of pathogens on seed tubers is essential for informing likelihood of subsequent potato disease. Here we utilized quantitative PCR assessment of pathogen DNA and visual assessment of disease to measure seed tuber inoculum and used this to model development of disease in potato grown in pathogen-free soil. Analysis by recursive partitioning and modeling using receiver operating curves indicated both abundance of Rhizoctonia solani AG3 and Streptomyces scabies DNA, and disease symptoms associated with these pathogens on seed tubers could predict subsequent disease in progeny tubers and for R. solani, stolons. In contrast, abundance of Spongospora subterranea DNA and disease symptoms on seed tubers were not consistently associated with powdery scab in progeny tubers. The relationship between S. subterranea DNA and seed tuber symptoms on root galling was stronger. Symptomless seed tubers that carried high levels of S. subterranea DNA were also associated with greater root galling than those with low pathogen DNA levels. There was a modest association between root galling and powdery scab in progeny tubers. These results highlight the importance of using certified seed tubers, and demonstrate a statistical tool for measuring the impact of seed tuber-borne inoculum.
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36

Webster, Theodore M., and Timothy L. Grey. "Halosulfuron Reduced Purple Nutsedge (Cyperus rotundus) Tuber Production and Viability." Weed Science 62, no. 4 (December 2014): 637–46. http://dx.doi.org/10.1614/ws-d-14-00032.1.

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Weeds persist and cause economic losses in agricultural systems because they exploit underused portions of that system. Reducing the effect of weeds on agroecosystems begins with minimizing the number of propagules (e.g., seeds and tubers) that are produced and returned to the soil. Purple nutsedge is a problematic weed around the globe, persisting between growing seasons as tubers in the soil. Halosulfuron is an effective herbicide for controlling purple nutsedge foliage and is used in corn and several vegetable crops. Studies were conducted to evaluate the effect of various rates of halosulfuron on purple nutsedge tuber production. Single, presprouted purple nutsedge tubers were transplanted into outdoor microplots and treated after 6 wk of growth with six rates of halosulfuron (7 to 208 g ai ha−1) POST with a nontreated control (NTC). All shoots that had emerged at the time of application were marked with plastic rings; this allowed for classification of tubers at exhumation of (1) tubers attached to shoots that had emerged by the time of application, (2) tubers attached to shoots that emerged after application, and (3) tubers without an aerial shoot during the study. Seven weeks after application, the tubers in the microplots were exhumed and tubers were classified, quantified, and their ability to sprout was evaluated. In the NTC, there were 530 total tubers, with a log-logistic regression model describing the tuber population with increasing halosulfuron rate. The rate of halosulfuron that reduced total tuber population 50% (I50) was 8 g ha−1. In the NTC, 200 tubers were attached to shoots that emerged following halosulfuron application, and this class of tubers had anI50of 19 g ha−1. Viability of tubers with shoots that emerged following halosulfuron application was 28% at the 52 g ha−1halosulfuron, suggesting the action of the herbicide may have rendered the tuber nonviable after new shoots were produced. The final classification of tubers was those that did not have an aerial shoot during the study. These were tubers in which apical dominance suppressed shoot development or were likely the most-recent tubers to develop. Of the three classes, the tubers without shoots were the most numerous in the NTC, with 294 tubers and anI50of 1 g ha−1. Halosulfuron is an effective herbicide that not only controls purple nutsedge foliage but also reduces the number of new tubers produced and overall tuber viability. This could be an important component to reduce the long-term population density of the weed.
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37

HOSSAIN, M. J., M. S. NAHAR, and A. U. AHMAD. "Sprout and top-shoot cutting for rapid multiplication of potato in Bangladesh." Journal of Agricultural Science 132, no. 4 (June 1999): 437–43. http://dx.doi.org/10.1017/s0021859699006565.

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The combined effect of two rapid multiplication techniques (sprout and top-shoot cutting) was assessed using four Dutch potato cultivars during 1991/92–1993/1994 at the Tuber Crops Research Centre (TCRC), Bangladesh Agricultural Research Institute (BARI), Gazipur-1701, Bangladesh. On average, a 70–80 g tuber produced 29 sprout cuttings which were subsequently used for taking top-shoot cuttings. Top-shoot cuttings were taken at a number of dates from 25 November and continued at 10 day intervals, thereafter, until 15 January. The number of top-shoot cuttings produced by 29 sprout cutting-derived plants varied (P<0·01) from 761 to 663 across the cultivars. Cardinal gave the greatest yield. Most of the characters studied varied (P<0·01) between cultivars but not over years while the interaction between cultivars and years was significant (P<0·01).Early planted top-shoot cuttings produced more tubers per plant (4·0) with a greater mean tuber weight (>22 g) than from the late planting (1 tuber and 5·5 g). On average, about 2·8 tubers per plant were produced with a mean tuber weight of 15·8 g. Cardinal and Patrones produced the most tubers per plant (2·9) and Diamant the greatest mean tuber weight (16·8 g). Cardinal gave the greatest yield (P<0·01) of tubers (268) followed by Patrones (241). The 29 sprout cutting plants derived from a 70±5 g tuber produced 160 tubers while the 771 top-shoot plants derived from 29 sprout cutting-derived plants produced 1420 tubers. The rate of multiplication of the combined two RM techniques was 1580[ratio ]1 against 11[ratio ]1 for the conventional method.
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38

Goktepe, Fahrettin, Zhanao Deng, Brent K. Harbaugh, Teresa Seijo, and Natalia A. Peres. "Techniques to Evaluate Caladium Cultivars for Host Resistance to Fusarium Tuber Rot." HortScience 41, no. 4 (July 2006): 1001D—1002. http://dx.doi.org/10.21273/hortsci.41.4.1001d.

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Caladiums, widely used in containers and landscapes as ornamental plants for their bright colorful leaves, are generally forced or grown from tubers. Commercial production of these tubers in central Florida is through dividing “seed” tubers and growing them in fields. Tuber quality is therefore of critical importance to success in container forcing, landscape use, and tuber production. Fusarium tuber rot (Fusarium solani) has been recognized as the most-destructive disease that affects caladium tuber quality. There is anecdotal evidence from growers indicating the existence of resistance in commercial caladium cultivars. To identify and confirm the source of fusarium tuber rot resistance in caladium, F. solani isolates have been collected from rotting tubers grown under different soil conditions and from different locations. The pathogenecity of these isolates has been tested through artificial inoculation of fresh harvested and/or stored tubers, and a number of highly virulent isolates have been identified. These isolates have been used to refine inoculation and disease evaluation techniques. Two techniques, spraying a conidial suspension onto fresh cut surfaces and inserting Fusarium-infested carnation leaf segments into artificial wounds, have proven to yield consistent resistance/susceptibility ratings among cultivars of known difference in resistance to fusarium tuber rot. Appropriate incubation temperatures and humidity seem to be very critical for disease development and evaluation. The two techniques have been used to evaluate 35 cultivars. Several cultivars, including `Candidum', showed a high level of resistance to fusarium tuber rot, and may be good breeding parent for developing new resistant cultivars.
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39

Gunter, Christopher C., and Jiwan P. Palta. "555 The Impact of Supplemental Calcium Fertilization during Potato Seed Tuber Production on Subsequent Crop Performance." HortScience 34, no. 3 (June 1999): 542A—542. http://dx.doi.org/10.21273/hortsci.34.3.542a.

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Tuber tissue calcium has been linked to several potato quality characteristics, including internal defects and the susceptibility of tubers to decay by soft rotting Erwinia species. We were particularly interested in studying the relationship between supplemental calcium fertilization during the seed tuber production cycle to raise the seed piece calcium concentration and the impact on crop performance the following season. The role of seed tuber tissue calcium level on seed piece decay, growth, development, and performance of the plant was evaluated for cultivars Russet Burbank, Dark Red Norland, Atlantic, Superior, and Snowden. This study was performed over four growing seasons. Seed tubers were raised with varying calcium and the following season, individual tubers (over 3,000 total for 4 years of study) were sampled for calcium and hand planted in the field. They were evaluated for seed piece decay and total tuber yield during the growing season. Seed tubers raised with supplemental calcium resulted in significantly higher mean calcium content than the control tubers. In general, calcium-raised seed tubers tended to produce a more vigorous main sprout and higher tuber yield. We also found that there are significant differences among these cultivars for the characteristics measured. Consistently, in all three years, `Atlantic' responded to test conditions with the lowest decay values, and `Dark Red Norland' consistently showed the highest decay values. This suggests that there may be a genetic component involved in these two responses and these genotypic differences could be exploited to improve cultivated potatoes.
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40

Bangarwa, Sanjeev K., Jason K. Norsworthy, and Edward E. Gbur. "Effects of Shoot Clipping–Soil Disturbance Frequency and Tuber Size on Aboveground and Belowground Growth of Purple and Yellow Nutsedge (Cyperus rotundusandCyperus esculentus)." Weed Technology 26, no. 4 (December 2012): 813–17. http://dx.doi.org/10.1614/wt-d-12.00041.1.

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Purple and yellow nutsedges are two of the world's worst weeds, reproducing asexually by rhizomes that can develop into new shoots or tubers. These tubers are the storage organs for carbohydrate reserves that are replenished by growing shoots and exhausted by new shoot, root plus rhizome, and basal bulb production. Based on the biology of both species, we hypothesized that the regenerative potential of purple and yellow nutsedge would decrease, with increasing shoot clipping–soil disturbance (SCSD) frequency and decreasing tuber size. To test this hypothesis, greenhouse experiments were conducted in pots to determine the effect of SCSD frequency and tuber size on aboveground and belowground growth of purple and yellow nutsedges. Five viable tubers of two tuber category sizes (small, 0.40 ± 0.05; and large, 0.80 ± 0.05 g of tuber fresh weight) were subjected to four SCSD frequencies (weekly, biweekly, monthly, and none) for 12 wk. SCSD was performed by clipping the emerged nutsedge shoots followed by manually disturbing the soil. SCSD at biweekly or weekly intervals reduced purple nutsedge proliferation, regardless of initial tuber size. However, monthly SCSD did not suppress purple nutsedge as effectively as weekly or biweekly SCSD, and less proliferation occurred with small tubers than with large tubers. In contrast, yellow nutsedge proliferation was equally reduced with monthly or more-frequent SCSD, regardless of initial tuber size. Even weekly soil disturbance for 12 wk failed to eradicate all small or large tubers in either species. Thus, yellow nutsedge is managed more easily than purple nutsedge with less-frequent tillage or cultivation. However, tillage or cultivation alone during a 12-wk period will not likely eradicate either nutsedge species from infested soil.
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41

Zhao, Chang Ling, Guo Song Wen, Zi Chao Mao, Shao Zhong Xu, Zheng Jie Liu, Ming Fu Zhao, and Chun Lin. "Molecular Structures of the Stem Tuber Anthocyanins of Colored Potatoes and Their Coloring Effects on the Tubers." Natural Product Communications 10, no. 3 (March 2015): 1934578X1501000. http://dx.doi.org/10.1177/1934578x1501000322.

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This paper summarized the important achievements about the general characteristics of the molecular structures of the stem tuber anthocyanins of Colored potatoes and the basic coloring effects of the anthocyanins on the tubers. The various coloration patterns of the skins and/or flesh of Colored potato tubers result from the accumulation of the anthocyanins in the periderms, phelloderms and/or peripheral cortices of the tubers, and the tuber colors are fundamentally determined by the matching profiles of the six naturally occurring anthocyanidins, i.e., cyanidin, delphinidin, malvidin, pelargonidin, peonidin and petunidin. Generally, the tuber anthocyanidins hold an O-glycosidic bond-linked rutinosyl at the C3 site, and either a glucosyl linked by an O-glycosidic bond or no substituent group may exist at the C5 site simultaneously. Furthermore, an E-monoacyl frequently exists at the C3- rutinosyls or at the C5-glucosyls of most tuber anthocyanins, and the phenolic acids acylating the tuber anthocyanins are often p-coumaric, ferulic and caffeic acids. The popular names of the p-coumaric acid derivatives of the malvidin, pelargonidin, peonidin and petunidin of the tubers are Malvanin, Pelanin, Peonanin and Petanin, respectively. This review provides a reference for the exploration of the mechanism of the tuber coloration and the identification of the molecular structures of the stem tuber anthocyanins of Colored potatoes.
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42

Rasocha, V., E. Hausvater, and P. Doležal. " Evaluation of characteristics affecting the market value of table potatoes after washing ." Plant, Soil and Environment 52, No. 6 (November 17, 2011): 245–49. http://dx.doi.org/10.17221/3436-pse.

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Skin scuffing is a problem of washing of the individual potato varieties, which is particularly important at harvests of physiologically immature tubers. Washing of such tubers cannot be recommended. Discoloration of scuffed tuber parts is another problem, which is exhibited by gray, brown to black color. Greening of washed tubers is mostly influenced by storage manner that also affects tuber sprouting. Mechanical damage, occurrence of several diseases, abiotic injuries, pest damages is also a problem. Various responses of potato varieties were found to tuber washing. Varieties with rough, netted skin, physiologically immature tubers, infected with diseases, mechanically damaged, susceptible to soft rot, expressing abiotic changes are not suitable for the washing. Tubers of varieties with smooth and bright skin, without scuffing, with later greening in the light, free of disease and abiotic injury presence and non-damaged by pests are suitable for washing. From this view the best results of tuber washing were obtained with varieties and hybrids: Ad&eacute;la,Astoria, Belladonna, Dali, Ditta, Flavia, Futura, Katka, Kordoba, Kornelie, Lady Christl, Laura, Milva, Princess, Redstar, Rosara, Samantana, Satina, Secura, Velox,Vera,Victoria, KE 524-11, KE 12-83.
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43

PRITCHARD, M. K., and A. J. SIEMENS. "EFFECTS OF MEFLUIDIDE ON PERIDERM DEVELOPMENT AND STORAGE OF RUSSET BURBANK AND NORCHIP POTATOES." Canadian Journal of Plant Science 70, no. 2 (April 1, 1990): 575–83. http://dx.doi.org/10.4141/cjps90-072.

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The effects of preharvest, foliar applications of mefluidide (N-(2,4-dimethyl-5-(((trifluoromethyl)sulfonyl)amino)phenyl)-acetamide) to potato (Solanum tuberosum L.) plants on subsequent periderm development and on storage quality of Russet Burbank and Norchip tubers were investigated. Mefluidide application caused adnormal periderm development in tubers of both cultivars and resulted in increased tuber weight loss during storage due to enhanced water loss rather than to elevated respiration. Treatment with mefluidide 5 wk before harvest resulted in greater tuber weight loss in storage than treatment 7 wk before harvest. After ca. 26 wk storage, sucrose content generally increased in tubers from treated Russet Burbank plants but not in corresponding Norchip tubers. Despite a perceived periderm enhancement, the abnormal periderm development which increased water loss in stored tubers would suggest that mefluidide has little potential as a preharvest treatment to reduce tuber damage and improve storage of Russet Burbank and Norchip potatoes.Key words: Potato, mefluidide, storage, Russet Burbank, Norchip, periderm
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44

Neeser, Christophe, Renan Aguero, and Clarence J. Swanton. "Survival and dormancy of purple nutsedge (Cyperus rotundus) tubers." Weed Science 45, no. 6 (December 1997): 784–90. http://dx.doi.org/10.1017/s0043174500088974.

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Survival and dormancy of purple nutsedge tubers has not been studied quantitatively. Yet this is fundamental to our understanding of the population dynamics of this highly noxious weed. Field studies were conducted to determine the effect of age on tuber survival and dormancy. A modified exponential decay function accurately described the age-dependent decline in tuber survival. This model is biologically meaningful, has good statistical properties, and can describe a wide range of responses. Tuber population half-life was 16 mo, and the predicted longevity (99% mortality) was 42 mo. Burial depth at 8 and 23 cm had no significant effect on survival or dormancy. Tuber dormancy increased with age. After 18 mo, the proportion of dormant tubers in the surviving population was two-and-one-half times higher than in the 3-mo-old population. We report for the first time that tubers were able to enter a state of secondary dormancy after sprouting. The finding that tubers persist after sprouting has important implications for population dynamics of this species. This is also the first report of tuber predation by the larvae of a billbug.
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45

Tuomola, Elina, Hannu Rita, Paavo Kuisma, Susanne Somersalo, Eija Pehu, Kari Jokinen, and Jari P. T. Valkonen. "Occurrence of common scab in potato tubers after foliar treatment with glycinebetaine under glasshouse conditions." Agricultural and Food Science 5, no. 6 (December 1, 1996): 601–8. http://dx.doi.org/10.23986/afsci.72773.

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A single foliar spray with 2.5 mM glycinebetaine (GB) was applied on potato (Solatium tuberosum L.) cvs. Matilda, Sabina and Saturna grown in a sand bed infested with Streplomyces scabies (Thaxter) Waksman & Henrici at tuber initiation. A period of drought was maintained after GB treatment to enhance scab infection. Logit models were used to compare scab incidence in all harvested tubers (n = 622) and the type of scab in the symptomatic tubers (n = 382), whereas the tuber surface areas covered with scab lesions were compared using ANOVA. A 10 g increase in tuber weight increased the odds of scab incidence by 11.3%. Scab incidence was lowest in Sabina and highest in Matilda. Raised scab and superficial scab were common in all cultivars, but pitted scab developed only in a few tubers of Sabina and Matilda. Among the scabby tubers, the incidence of raised scab was highest in Sabina and lowest in Saturna. The mean surface area covered with scab was 32.8% in Matilda, 11.7% in Saturna and 7.5% in Sabina. Treatment with GB slightly reduced the severity of scab symptoms, as shown by the reduction in the proportion of tubers with raised scab among the scabby tubers (odds 0.60). No effect on the incidence of scab or the tuber area covered with scab lesions was detected following GB treatment.
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46

Edun, Bolanle Tolani, Yahuza Lurwanu, Mustapha Sunusi, and Rabi’u Shehu Aliyu. "Effect of Storage Methods and Management of Sweet Potato on the Incidence of Tuber Rot Induced by Rhizopus stolonifer in Kano, Nigeria." Journal of Tropical Crop Science 6, no. 01 (February 18, 2019): 8–16. http://dx.doi.org/10.29244/jtcs.6.01.8-16.

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Different storage methods and management practices of sweet potatoes in Kano state, northwestern Nigeria, were investigated to fi nd out how they may affect the incidence of tuber rot. Three local government areas were selected for the sample collection. In each local government area, two sweet potato farming communities were selected, infected and uninfected tubers were sampled and taken to the laboratory for further studies. Pathogenicity test confi rmed Rhizopus stolonifer as the causal pathogen responsible for tuber rot and this fungus was used for the inoculation of fresh sweet potato tubers in all the storage and management methods used in the experiment. Tubers preserved using ash + sand and fungicide + sand showed the least incidence of tuber rots. Similarly, it was also observed that storage of tubers with sand alone showed a reduction in the severity of the disease across the storage weeks. There was no signifi cant difference in the incidence and severity of tuber rot between the two inoculation methods with both the treatment combinations. Our result showed that the incubation period of R. stolonifer to infect sweet potato tubers started at two days after inoculation with about 25% infection. The result also indicated that none of the tubers treated with fungicide, ash, and eucalyptus sprouted at both the storage weeks, this may be attributed to the possibility of having some inhibitory properties against sprouting.
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47

O'BRIEN, P. J., D. M. FIRMAN, and E. J. ALLEN. "Effects of shading and seed tuber spacing on initiation and number of tubers in potato crops (Solanum tuberosum)." Journal of Agricultural Science 130, no. 4 (June 1998): 431–49. http://dx.doi.org/10.1017/s0021859698005541.

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Twelve field experiments, carried out over 7 years, examined effects of shading and seed tuber spacing on plant growth, initiation and retention of tubers in four cultivars: Estima, Maris Piper, Maris Peer and Record. Ten of the experiments were carried out at Cambridge and two near Valencia, Spain. Other treatments included in some experiments were floating polythene mulch and planting date.Shading by up to 75% did not affect the timing of onset or cessation of tuber initiation in Estima but shading by 50% or more delayed the completion of tuber initiation in Maris Piper compared with less severe shading. Except for intensely shaded treatments (50% or more), the majority of tubers were initiated in a very short period (4–7 days). Shading by 37% or more during the period of tuber initiation and increasing planting density, decreased number of tubers per stem initiated in all experiments, but number of tubers was not affected by shading at other stages of growth. At Cambridge, effects of shading on number of tubers >10 mm retained later in growth from normal planting dates (March to early May) were similar to effects on number of tubers initiated, but effects were much reduced or absent following later plantings at Cambridge and in both experiments in Valencia. The decreased effects of shading on number of tubers >10 mm at late plantings at Cambridge were associated with the initiation of fewer tubers at these plantings. Effects of shading, planting density and planting date on number of tubers were a consequence of changes in the frequency of occurrence and tuberization of different stolon types. Increasing shading and planting density and delaying planting reduced the number of lateral and branch stolons and the frequency of their tuberization but there were no effects on number of primary stolons or their tuberization. Consequently, at Cambridge a similar number of tubers was borne on primary stolons in shaded and unshaded crops. In Valencia a greater proportion of initiated tubers was retained at final harvest from shaded treatments than at Cambridge, which accounts for the absence of effects of shading on number of tubers >10 mm. The greater retention of tubers late in growth in Spain may have been associated with the higher peak growth rates achieved in higher radiation fluxes than at Cambridge.Linear regressions of the data for normal planting dates at Cambridge and from Valencia indicated that the number of tubers >10 mm late in growth was dependent on the radiation environment during the period of tuber initiation. Radiation flux during the brightest period of the first few days of initiation appeared to be the most crucial aspect of radiation affecting number of tubers. As incident radiation can vary greatly over the short period of tuber initiation, it is potentially an important factor affecting number of tubers in field crops.
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48

Sadawarti, Murlidhar J., S. P. Singh, R. K. Singh, Subhash Katare, and R. K. Samadhiya. "Agro-techniques for Production of Seed Size Tubers in Conventional Seed Potato Production System–A Review." International Journal of Bio-resource and Stress Management 12, no. 3 (June 30, 2021): 238–46. http://dx.doi.org/10.23910/1.2021.2272.

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The seed potato cost is very important component in total potato production and account for 30 to 70% which varies depending on the country or region. Tuber size is an important factor to decide the seed requirement per unit area. Seed size affects total yield, graded or marketable tuber yields. Standard seed tuber of 25–125 g weight (30–55 mm) is known as seed size tubers in India. Obtaining seed size tuber is important for achieving higher potential of the cultivars. The tuber size profile can be reduced or expanded by altering inter and intra row seed spacing, controlling days of growth by planting late or killing vines/haulm early, regulating inputs like fertilizer and water etc. An ideal combination of plant population, row width, and in-row seed spacing for a particular variety were the major factors for optimizing tuber size. Variation in tuber bulking ability in different genotypes results in variation in proportion of seed size tubers among different varieties. 70–80 days haulm killing found most suitable for getting higher proportion of seed size tubers in high bulking varieties. Proper management of N, P and K fertilizers is considered very important to maximize tuber yield and attain desirable quality. Variability in nitrogen dose/ha was observed which ranged from 100–150 between different regions of the world. Hence proper combination of above Agro-techniques should be adopted in seed production programme as per the region for getting higher proportion of seed size/plantable seed tubers.
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49

Kleinhenz, Matthew D., Jiwan P. Palta, Christopher C. Gunter, and Keith A. Kelling. "Impact of Source and Timing of Calcium and Nitrogen Applications on `Atlantic' Potato Tuber Calcium Concentrations and Internal Quality." Journal of the American Society for Horticultural Science 124, no. 5 (September 1999): 498–506. http://dx.doi.org/10.21273/jashs.124.5.498.

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Three Ca sources and two application schedules were compared for their effectiveness for increasing tissue Ca concentrations in 170 to 284 g field-grown tubers of `Atlantic' potato (Solanum tuberosum L.). Additional observations were made of internal physiological defects. Paired measures of tissue (periderm and nonperiderm) Ca concentration and internal quality (±hollow heart, ±internal brown spot) were made on individual tubers produced in plots fertilized with N at 224 kg·ha-1 and Ca at either 0 or 168 kg·ha-1, supplied from either gypsum, calcium nitrate or NHIB (9N-0P-0K-11Ca, a commercial formulation of urea and CaCl2). Application of N and Ca at emergence and hilling (nonsplit) was compared to application at emergence, hilling, and 4 and 8 weeks after hilling (split). Tuber yield and grade were unaffected by treatments. Split Ca application (from either calcium nitrate or NHIB) increased mean tuber nonperiderm tissue Ca concentrations and the percentage of tubers with an elevated Ca concentration in both years compared with non-Ca-supplemented controls. Split Ca application also resulted in greater increases in Ca in nonperiderm tissue than nonsplit Ca application in 1994. Although the correlation coefficient between Ca level in periderm and nonperiderm tissue of >400 individual tubers was highly significant in both study years, linear regression analyses suggested the Ca level in the two tissues were poorly related. Split application was associated with a 37% reduction in the incidence of internal tuber defects, relative to nonsplit application in 1994. Calcium application did not affect tuber internal quality based on means analysis, but chi-square analysis suggested that Ca concentration and internal quality of individual tubers may be related. The incidence of internal defects was 16.4% in tubers with nonperiderm tissue Ca >100 μg·g-1 dry weight compared to 10.6% in tubers with nonperiderm tissue Ca >100 μg·g-1 dry weight. These data suggest that 1) it is feasible to increase tuber Ca levels by field applications of moderate amounts of Ca, 2) tuber quality is impacted by N and Ca application schedule, and 3) Ca concentrations in tuber periderm and nonperiderm tissues may be controlled independently.
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50

Ivanova, K. A., E. G. Komyshev, M. A. Genaev, A. A. Egorova, K. A. Koloshina, N. A. Chalaya, D. A. Afonnikov, A. V. Kochetov, E. V. Rogozina, and S. V. Gerasimova. "Image-based analysis of quantitative morphological characteristics of wild potato tubers using the desktop application SeedСounter." Vavilov Journal of Genetics and Breeding 23, no. 5 (August 24, 2019): 519–26. http://dx.doi.org/10.18699/vj19.35-o.

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The development of quantitative digital phenotyping methods for evaluation of wild potato (section Petota Dumort., genus Solanum L.) tuberization is required for annotation of genebank collections and selection of the suitable donor material for potato breeding. There are no available methods specifically designed for the quantitative analysis of wild potato tuber morphology. The current study is devoted to evaluation of wild potato tubers’ morphological characteristics using a digital image processing technique. For this purpose, the mobile application SeedSounter developed previously for grain analysis was specifically adapted for tuber phenotyping. The application estimates the number and shape of objects scattered on a standard sheet of white paper (i. e. A3 or A4). Twelve accessions from the VIR genebank collection belonging to nine Petota species were grown in pots protected with garden fabric during the growing season of cultivated potato (Novosibirsk region). Tubers were collected form plants of nine genotypes. Three genotypes did not produce tubers. The weight of tubers collected from each plant was measured. The tuber yield from each plant was analyzed using SeedCounter (http://wheatdb.org/seedcounter). The number of tubers per plant was counted; the following characteristics were extracted from the images of individual tubers: length, width, projected area, length to width ratio, сircularity, roundness, rugosity and solidity. One-way ANOVA showed a significant effect of genotype on all measured characteristics. A pairwise comparison of nine Petota accessions using all measured parameters revealed statistically significant differences between 86 % of pairs. The overall tuber yield volume for each plant was calculated as a sum of volumes of individual tubers; tuber volume was calculated from its length to width ratio and projected area. A strong correlation between the evaluated tuber yield volume and yield weight was shown. We propose tuber yield volume as a characteristic for a general evaluation of tuberization for wild potato, implementing the four-step scale from 0 to 3. According to this characteristic, the twelve wild potato accessions studied could be divided into four groups with different tuberization abilities. The evaluated tuberization ability is partially in accordance with previously obtained VIR data. The results presented demonstrate the possibility to use SeedCounter for wild potato collections phenotyping.
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