Comparative performance of different-sized seed tubers derived from true potato seed

The growth and yield of plants from different-sized seed tubers derived from true potato seed were evaluated on a per stem, per plant, and per unit area basis using either single or multiple-sprout tubers. In single-sprout tubers, haulm dry weight per stem 47 days after planting was greater in the 40–60 g tubers when compared with that in the 5–10 g or the 10–20 g tubers. This resulted in greater tuber weight per stem in the 40–60 g tubers throughout the growing season. The number of tubers per stem was not affected by seed tuber size. In multiple-sprout seed tubers of increasing size, total tuber number and total tuber weight, as well as weight of those tubers larger than 45 mm, increased on a per plant basis but decreased on a per stem basis. At different rates of planting, 1–5 g seed tubers produced smaller tubers than 5–10 g or 10–20 g seed tubers. Increased rate of planting resulted in non-significant yield increases per unit area in plots planted with 1–5 g seed tubers. The yield increases were significant when 5–10 g and 10–20 g seed tubers were planted at higher rates. The number of main stems per unit of seed tuber weight was five times greater in 1–5 g tubers compared with that in 40–60 g tubers. This resulted in low seed weights per hectare when small tubers were planted and in a high ratio of harvested to planted tuber weight.     

Nitrogen fertilization and irrigation affects tuber characteristics of two potato cultivars

Nitrogen fertilization, irrigation, and cultivars affect tuber characteristics such as tuber size, specific gravity, and N concentration. Few studies, however, have investigated the interaction of irrigation and N fertilization on the tuber characteristics of potato cultivars, particularly in Atlantic Canada. The objective of this on-farm study, conducted at four sites in each of three years, 1995 to 1997, was to determine the effects of supplemental irrigation and six rates of N fertilization (0-250 kg N ha^-1) on the number of tubers per plant, the average fresh tuber weight, tuber N concentration, nitrate (NO₃-N) concentration, and specific gravity of the cultivars Shepody and Russet Burbank. Nitrogen fertilization increased the average fresh tuber weight, tuber N and N0₃-N concentrations, and decreased specific gravity. Effects of increasing N fertilization on tuber characteristics were often more pronounced for Shepody than for Russet Burbank, and for irrigated than for non-irrigated conditions. Shepody had greater average fresh tuber weight and tuber N concentration, lower specific gravity, and fewer tubers per plant than Russet Burbank. Supplemental irrigation increased the average fresh tuber weight and the number of tubers per plant, but it had a limited effect on specific gravity and tuber N and NO₃-N concentrations. Tuber NO₃-N con centration and specific gravity were strongly related to tuber N concentration, which in turn depended primarily on N fertilization. Incidents of lowest specific gravity and highest NO₃-N concentration occurred with a relative yield close to or equal to 1.0. We conclude that the risks of low specific gravity and high tuber NO₃-N concentration are greater when fertilization exceeds the N requirements to reach maximum tuber yield.     

Effect of supplemental nitrogen on true potato seed weight

The effect on true potato seed (TPS) weight of supplemental nitrogen (N) applied during seed development was investigated using crosses DTO-33 × R128.6 (“A” produced in the field) and Atzimba × R128.6 (“B” produced in the field and in a screenhouse). Dry weights of tops and tubers of the mother plants were also measured in the screenhouse. The response to supplemental N (0-240 kg/ha) in 100-TPS weight of cross A and B from the field was positive and linear. In the screenhouse, where higher total N (0-1200 kg/ha) was applied, the responses in 100-TPS weight and dry weight of tops and tubers were curvilinear, with maximum levels at 800, 1000 and 400 kg/ha, respectively. The 100-TPS weight of cross B was 40% higher in the field than in the screenhouse. In the field, increased frequency of supplemental N applications increased 100-TPS weight of large and medium berries of cross B, but had no effect on seed from small berries nor on seed from any berries of cross A. In the screenhouse, increased application frequency decreased tuber dry weight and increased dry weight of tops, but had no effect on 100-TPS weight. It was concluded that supplemental N must be applied during seed development and at higher total levels than those required for optimum tuber yields in order to maximize 100-TPS weight. The lower seed weight from the screenhouse suggests that other environmental factors (e.g., temperature) present during growth of the mother plant can affect the weight of the resultant TPS.     

马铃薯试管块茎形成机制的研究──BA对试管块茎形成与膨大的影响

试验以“米拉”脱毒苗为基础材料，研究了在不同光照和蔗糖浓度条件下，不同浓度ＢＡ以及不同时间加入ＢＡ对试管块茎形成与生长的影响．试验结果表明，ＢＡ与光照条件、蔗糖浓度之间在影响块茎形成和生长过程中不存在显著的互作关系，但三者均为块茎形成和膨大的必要条件．短日照有利于匍匐茎的发生，ＢＡ有利于匍匐茎顶端的膨大，蔗糖浓度与块茎大小和数量有密切关系．本文涉及的试验中，每天光照８小时，蔗糖浓度为８％，使用２ｐｐｍＢＡ在转入短日照８～１０天后加入对块茎的形成与膨大效果最好，最后有效单株块茎数达２．２４和２．２６个。     

Selection of Yield-Associated Morphological and Biochemical Traits Using Correlation and Path Coefficient Analysis in Potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) in the Foothills of North-Western Himalayas

The objective of the study was to assess the direct and indirect effects of 13 important morphological and biochemical traits on yield enhancement in 28 advanced breeding lines of potato (Solanum tuberosum L.) in the foothills of north-western Himalayas. Tuber yield was positively correlated with number of tubers per plant (r?=?0.76), number of stems per plant (r?=?0.53), number of leaves per plant (r?=?0.43) and tuber weight (r?=?0.37). Furthermore, tuber yield exhibited a significant negative correlation with days to maturity (r?=???0.39). Days to 50% emergence had a significant negative correlation with protein content (r?=???0.42). Path analysis revealed that the components of yield, number of tubers per plant and tuber weight, had high positive direct effects (0.876 and 0.618, respectively) on tuber yield, whereas the effects of other traits were low (≤?0.128). Furthermore, tuber weight had an indirect negative effect on tuber yield through the number of tubers. Tuber size had a low correlation (0.19) with tuber yield because a positive indirect effect (0.451) through tuber weight was balanced by a negative indirect effect (??0.254) through tuber number. The number of stems and number of leaves had positive indirect effects (0.377 and 0.377, respectively) on tuber yield through tuber numbers, whereas days to maturity had a negative indirect effect (??0.298) through tuber numbers. There were virtually no indirect effects through the biochemical traits. The implications for potato breeding are discussed.     

种植密度与马铃薯块茎大小的分布——Ⅱ.块茎大小分布的数学模型及其应用

本试验在3种不同的种植密度下,分期调查了马铃薯主栽品种Mira和783-1在田间的块茎大小分布。结果证明,块茎生长发育期间其大小分布为一负指数曲线形式,并可用数学模型y=N(e~(-λbn~(-1))-e~(-λbn))来表示(式中y为块茎重量等级n的块茎个数,N为单位面积的块茎总数,λ为块茎平均重量的倒数,b为块茎重量等级的上限)。即在一个块茎群体中,块茎数目以30g以下的小块茎为多,随着重量级别的增加,其数目逐步减少。高密度增加了小块茎的数目及其比例从而导致块茎的平均重量下降。统计分析表明,模型预测值与实际观测值无显著差异。根据上述模型,块茎的大小分布主要取决于单位面积上的块茎总数及块茎平均重量这两个参数。由于种植密度与块茎数目、光能截获量与块茎产量之间存在着显著的相互关系,因此根据对块茎大小的需求,该模型可帮助确定适宜的种植密度与收获晚期,来达到控制块茎大小的目的。     

Sequential Path Analysis of Yield Components in Potato

In order to determine proper selection criteria for tuber yield in potato clones obtained from true potato seed (TPS) and to evaluate relationships between tuber yield and its components, an investigation was conducted using the five check cultivars Agria, Marfona, Draga, Agata, and Arinda, and 120 potato clones obtained from TPS. The study was conducted in an augmented randomized complete block design with three replications. Yield and its components were recorded. Correlation coefficient analysis showed that tuber yield had significant positive associations with number of tubers per plant, average weight per tuber (tuber size), plant height, diameter of main stem, and number of main and secondary stems per plant, whereas its correlation with tuber dry-matter concentration was significantly negative. Number of tubers per plant, tuber size, and plant height had significant standardized partial regression coefficients with very small tolerance and large variance inflation factor (VIF) values. These were considered as the first-order variables in sequential path analysis.     

马铃薯无性一代植株性状相关及通径分析

本文对马铃薯30个杂交组合无性一代的14个性状与单株产量的相关关系作了估算,其中无效生育期、播后74天和92天冠层覆盖度、平均冠层覆盖度、最高冠层覆盖度、有效生育期、单株块茎数、单块重8个性状与单株产量的相关性达显著或极显著水平。进而对影响单株产量(y)的平均冠层覆盖度(x_1),有效生育期(x_2)、单株块茎数(x_3)、单个块茎重(x_4)进行通径分析。结果表明,该4个性状决定单株产量变异的94.61％,说明这4个性状是影响单株产量的决定因素。     

Efficacy of Seed Aging and Gibberellin Treatments for Manipulating Apical Dominance,Tuber Set and Size Distribution of cv. Shepody

The cultivar Shepody has excellent early processing qualities and produces above average tuber yields but sets relatively few tubers that often become excessively large relative to market demand. Optimizing tuber set and size of Shepody for seed and frozen processing markets currently entails adjusting in-row spacing and vine kill date. However, arresting tuber growth by vine killing for size control sacrifices yield potential. Aging seed by storing at 12, 22, and 32°C for 80-, 450-, and 900-degree days, or gibberellin (GA) treatments, were evaluated as more direct approaches for modulating stem number (apical dominance), tuber set, and size distribution relationships. Shepody proved to be inherently resistant to high temperature-induced age-priming treatments. In contrast to other cultivars studied previously, age-priming Shepody seed during storage had no effect on plant emergence and the resulting increases in stem number, tuber set, and associated decreases in average tuber weight were marginal. By contrast, GA applied as seed dip or spray effectively hastened plant emergence, reduced apical dominance, increased tuber set, and decreased average tuber size. The magnitude of these GA-induced effects depended on concentration and application technique (seed dip versus spray). For frozen processing, GA applied as a seed dip at 1 mg L^-1 added an additional tuber per plant and decreased average tuber size by 15% without affecting U.S. No. 1 tuber yields and gross returns; however, 2 and 3 mg L^-1 GA decreased U.S. No. 1 tuber yields and crop value by an average of 16 and 14%, respectively. Spray applications of 2–6 mg L^-1 GA also reduced U.S. No. 1 tuber yield and frozen processing value. Conversely, the increase in tuber set (1.5 tubers plant^-1) and associated 25% reduction in average tuber weight induced by 2 mg L^-1 GA applied as either dip or spray increased gross crop values on a seed contract by 25 and 38%, respectively. The differential efficacies of dip versus spray applications of GA on tuber set and size distribution were likely attributable to differences in GA deposition on the seed. Applying low concentrations of GA to cut seed of Shepody as either a dip (1–2 mg L^-1) or spray (2 mg L^-1) effectively modulated tuber set and size to significantly increase gross returns for seed, and to better satisfy the needs of processors for more moderate size tubers.     

株行距和施肥量对木薯产量及生长的影响

采用裂区试验设计方法,研究株行距和施肥量对华南5号木薯产量和生长的影响.结果表明:在本试验株行距和施肥量条件下,施肥量对木薯产量和生长的影响比株行距大.密植(0.6～0.8 m)有利于提高淀粉产量、鲜薯产量和鲜薯淀粉含量,以0.8m株行距最佳,而疏植(1.2～1.4m)有利于提高单株薯数、单株鲜薯重、单株鲜茎叶重、收获指数和茎径.施肥有利于提高淀粉产量、鲜薯产量、单株鲜薯重、单株鲜茎叶重、茎径、株高和单株薯数,但降低鲜薯淀粉含量和收获指数.丰产栽培技术要兼顾单位面积株数、单株鲜薯重和鲜薯淀粉含量.建议在土壤肥力差和少施肥时,用0.6 m株行距;土壤肥力中等且较高施肥时.采用0.8 m株行距;土壤肥力中上且优越水肥管理,采用1.0 m株行距.     

氮肥基追肥比例对马铃薯微型薯生产的影响

为探讨马铃薯微型薯合理的氮肥施肥方式,以‘早大白’马铃薯脱毒试管苗为材料,在温室内进行了氮肥不同基施和追施比例对马铃薯微型薯生产影响的试验。结果表明:在施氮肥量为纯氮105 kg/hm2条件下,单株结薯方面,基追比为5:2时,单株结薯最多,全部做基肥的处理,单株结薯最低;单粒重方面,基追比为2:1时,单粒重最大,全部追肥的处理最低。可见氮肥基施和追施配合有利于提高单株结薯率及平均单粒重。因此,微型薯生产重视氮肥基施同时配合追施比较符合移栽的试管苗对氮肥的吸收规律。     

马铃薯库建成动态研究

在马铃薯块茎的形成和增长过程中 ,小薯不断地形成、退化或转化成大中薯 ,其中出苗2 8d以后的 2～ 3周是决定大中薯数的关键期。在不同密度及施肥处理下 ,马铃薯块茎体积及干重的增长均呈S型曲线变化。单株块茎体积随密度增加而减少 ,适量施用氮、磷、钾 ,可增加块茎体积、单株结薯数和大中薯数 ,其中磷钾肥可使结薯时间提前 ,过量氮肥则推迟结薯时间 ;随密度的增加 ,块茎日增重逐渐降低 ,适量增施磷、钾肥可提高库的充实度 ,增加产量。在本试验因素中量 (适量 )组合 ,底西芮品种单株块茎体积最大增长速率为 2 5 7392ml d ,块茎干重的最大增长速率为 10 6 82 6 g d ;种植密度 4 5 0 0株 6 6 7m2 时 ,单株结薯数为 13 5个 ,大中薯数平均为 10个 ,单产可达 30 0 0kg 6 6 7m2 以上     

马铃薯器官生长发育与产量形成的研究

马铃薯叶面积、叶干重以及块茎干物重和块茎体积的变化动态均符合三次曲线变化 ,地上茎干重、茎粗、株高符合S型曲线变化 ,其中 ,叶干重的峰值早于叶面积的峰值 ,块茎体积的增长则在出苗后 5 5～ 70d内最快。马铃薯地上茎的生长主要是伸长与充实 ,但伸长较充实缓慢、持续时间更长。匍匐茎与块茎的形成是马铃薯产量形成的前提条件 ,二者的建成与植株其它器官的生长发育密切相关 :匍匐茎和块茎的形成与叶片和地上茎形成时期并进 ,所以 ,马铃薯块茎的建成与地上营养器官的生长发育存在着光合产物的竞争 ,但地上部器官的建成依然是产量形成的物质基础。     

Impact of early-season water deficits on Russet Burbank plant development,tuber yield and quality

Russet Burbank potatoes grown on Owyhee silt loam were subjected to early-season moisture stress by delaying initiation of furrow irrigation up to seven weeks after planting. A range of water stress treatments from 4 to 7 weeks after planting resulted in reduced plant size, tuber number and total tuber weight per plant 8 1/2 weeks after planting. Early-season water stress resulting from delayed irrigation onset was associated with improved tuber quality at harvest. Plants water stressed before tuber initiation had fewer tubers with dark stem-end fry colors, reduced percentage of US No. 2 potatoes, and increased percentage and size of US No. 1 potatoes. Increasing duration of soil water potential below -60 kPa early in the season was associated with declining total yield in 1985 but not in 1986. To obtain optimum yield and processing quality, the first irrigation should be no sooner than full plant emergence.     

The feasibility of predicting the number of stems per tuber produced by potato seed stocks from measurements made before planting

Summary The number of stems per seed tuber produced by 17 seed stocks of cv. Record was determined in glasshouse and field experiments to assess the feasibility of predicting the number of stems produced in the field. Multiple regression analysis showed that seed tuber weight alone gave the most satisfactory fit to stems produced in the field, which was not improved by adding terms involving the number of stems produced in the glasshouse. Quadratic relationships between the number of above-ground stems per tuber and tuber weight were most appropriate for each stock, with the fitted curves for individual stocks differing only in the constant term. However, there were significant rank correlation coefficients between the constant terms for relationships between field stems and tuber weight and glasshouse stems and tuber weight, suggesting that in other cultivars and seed stocks a predictive glasshouse test might still be useful.     

Effect of Nitrogen Rate on Growth,Yield, Economics and Crisps Quality of Indian Potato Processing Cultivars

A field study was conducted during 2000–2001 and 2001–2002 at the Central Potato Research Institute Campus, Modipuram, India, in order to increasing the processing-grade tuber yield of India’s first ever developed processing potato cultivars, Kufri Chipsona-1 and Kufri Chipsona-2. Tuber yield and post-harvest quality characteristics were evaluated in response to five N levels (0, 90, 180, 270 and 360 kg N ha^-1). The crop growth traits (stem number, plant height and compound leaf number) responded positively to N application, whereas the effect of N fertilization on processing-grade tuber number, total tuber number per ha and tuber number per plant was quadratic. There was a steady increase in tuber weight per plant, processing-grade tuber yield, total tuber yield and biomass yield in response to N application. Kufri Chipsona-1 produced a 23.6% higher tuber yield per plant than Kufri Chipsona-2. Agronomic N use efficiency decreased linearly with increased N doses. Specific gravity and tuber dry matter percentage responded positively to N application, while crisps colour (at harvest and after storage) and reducing sugars remained unaffected. Cultivar was the major factor that influenced the tuber quality parameters (specific gravity, crisps colour). Higher values of these quality traits were observed in Kufri Chipsona-2 as compared to Kufri Chipsona-1. Net income and benefit cost ratio (B:C) indicated that Chipsona cultivars should be fertilized with 270 kg N ha^-1 for realizing higher processing-grade yields and desirable quality tubers.     

磷酸二氢钾对雾培马铃薯脱毒种薯增产的研究

通过对5个不同浓度梯度的磷酸二氢钾(KH2PO)4溶液和1个空白对照(CK)在薯块膨大期喷施雾培马铃薯叶片,探索叶面喷施KH2PO4对雾培马铃薯脱毒种薯增产的影响。结果表明,叶面喷施1～5g·L-1的KH2PO4可极显著增加匍匐茎和1 g以上种薯数量,提高大薯率和单株产量,其中以喷施4 g·L-1 KH2PO4效果最好。     

Field performance of potato minitubers with different fresh weights and conventional seed tubers: Multiplication factors and progeny yield variation

Summary Multiplication factors and progeny yield variation in crops from minitubers of five weight classes (ranging from 0.13–0.25 g to 2.00–3.99 g) and conventional seed tubers were studied in field experiments in three years. Multiplication factors were calculated as the number and weight of progeny tubers produced per planted tuber or per unit planted tuber weight. They were lower for the lighter minitubers when calculated per tuber and higher when calculated per weight. Yield variation was described by coefficients of variation for the number and weight of progeny tubers produced. Variation over individual plants of a crop was higher in stands from the lighter minitubers. Variation over plots within a field was sometimes higher for the lighter minitubers, but variation over years was similar for all minituber classes. Variation over plots in progeny tuber weight was higher for minitubers than for conventional tubers.     

Influence of plant spacing on potato (Solanum tuberosum L.) morphology,growth and yield under two contrasting environments

Summary In experiments at a temperate (43^oN) and a tropical (14^oN) location, closer plant spacing decreased stem branching, root growth, and mean tuber size but increased tuber yields per ha. Closer spacing increased plant height at the temperate site but decreased it at the tropical site where canopy cover did not reach 100%. The increased branching at the wider spacing did not compensate for fewer plants/m². Total and tuber weight per plant increased with wider spacing and was much greater under temperate than tropical conditions. Tuber yield/stem also increased with lower stem densities. Although these results provide initial data for modelling, the contrast between the two environments and interactions between spacing and cultivar suggest that further experiments need to be done with a range of cultivars at intermediate locations.     

马铃薯脱毒试管苗在不同扦插密度条件下的产量性状和经济参数的分析

为了探讨马铃薯脱毒试管苗在温室条件下的适宜扦插密度问题,利用早熟品种荷兰15号、中熟品种尤金和中晚熟品种克新13号的脱毒试管苗为试验材料,种植并生产原原种。采用单因素随机设计,设密度分别为每平方米154株、182株、222株、286株、400株和667株共6个处理,用方差分析探讨了扦插密度与结薯个数(单位面积上的商品薯数、单株商品薯数、单位面积上的结薯总个数、单株结薯总个数)、产量参数(单位面积上的商品薯产量、单株商品薯产量、单位面积上的总产量、单株产量)和经济参数(利润和经济效益)的关系。研究结果表明:荷兰15号、尤金和克新13号的脱毒试管苗扦插密度每平方米在154～667株之间时,随着扦插密度的增大,其结薯总个数均逐渐增多,单株商品薯产量和单株产量均逐渐变低;这3个品种在每平方米上的商品薯产量、总产量、利润和经济效益的变化趋势不同;通过结薯个数和经济参数的综合评价,得出荷兰15号和尤金的适宜扦插密度每平方米为400株,克新13号的适宜扦插密度为286株。