Potato (Solanum spp.) in an isohyperthermic environment II. Response to planting date

The potato has only recently been introduced into isohyperthermic environments, and is grown during the dry season. There is a need to determine the optimum planting time and the range of possible planting dates. Two contrasting cultivars, ‘Cosima’ and DTO-2, were studied to determine the influence of planting date on their growth and development. They were planted on five dates from early to late dry season (October-January) during two years, at 14° N lat. in The Philippines. Another objective, studied during the second year, was to compare seed produced under hot lowland conditions and stored for 8 months, with newly sprouted seed grown under cool highland temperatures.Potato plants grew faster and tuberized earlier for later planting dates. Physiologically young seed of Cosima and DTO-2 always produced plants with superior canopies. Tuber bulking was linear up to about 70 days after planting. Total dry-matter production was highest with young Cosima seed, exceeding 100 g plant⁻¹ for all planting dates except the last. Old Cosima and DTO-2 seed generally produced between 80 and 100 g dry matter plant⁻¹. Final tuber yields were highest with the mid dry-season planting (December) during both years with highland seed Cosima yielding 30 t ha⁻¹. Lowland seed of Cosima yielded over 21 t ha⁻¹ for the first 4 planting dates, significantly less than yields from highland seed. Yield differences increased with later planting. Although highland seed is recommended, lowland seed is an alternative for poor farmers. The final tuber yield of Cosima decreased by 12% with a minimum air temperature rise from 18.5 to 21° C, while DTO-2 was more adversely affected. Based on these results, minimum ait temperatures above 21 °C are unsuitable for potato production. Total intercepted solar radiation was positively correlated with final tuber yields and total dry-matter production. Efficiency of conversion into dry matter was about 70% of that in cool temperate climates.     

Growth-room and field studies with seed tubers treated with ethylene and 1-methylcyclopropene (1-MCP) during storage

Based on ethylene management in potato storage, we hypothesized that the applied treatments would modify number of sprouts per seed tuber. Thus, in combination with in-row spacing (closer for seed, wider for processing) in the field treatments will give either (1) a high number of small tubers destined for seed use, or (2) a relatively smaller number of large, uniform tubers suitable for processing. A three-year study (2001–2003), conducted with two french fry processing cultivars, Russet Burbank (RB) and Shepody (SH), aimed at the development of a novel modified atmosphere seed tuber storage treatment. Seed tubers were stored at 4 C from October to May of each year in a cold room under five modified atmospheric regimes: (1) air ventilation only (Control); (2) 4 µl L^?1 ethylene applied continuously beginning in November and (3) beginning in February; (4) 1 µ1 L^?1 MCP (1-methylcyclopropene) applied as a gas for 48 h only in early December followed by continuous 4 µl L^?1 ethylene and (5) MCP alone applied as above. Each year, once a month (mid-January until end of April), a number of seed tubers was taken from each storage treatment, planted to pots and grown for 4 wk in a growth-room. In these studies, shoot emergence from the ethylene-treated seeds of both cultivars occurred significantly earlier, giving higher number of stems per tuber and stolons per stem than Control and MCP treatments. Moreover, the time to emergence after planting decreased with the increased length of storage. Field studies that were conducted from the end of May (planting) until October each year, produced similar trends (although not significant atP≤0.05) and resulted in a higher number of tubers per stem. In RB at the closer in row spacing (30 cm) used for seed production, ethylene enhanced yield of smaller tubers in the 30- to 115-g and 115- to 300-g categories. The ethylene storage treatments also increased tuber number per plant, but not the total mass of harvested potatoes. The MCP treatment, in combination with the wider in-row spacing (40 cm) used for the production of processing tubers, significantly increased the percentage of large tubers (>300 g). In SH, contrary to RB, the ethylene treatments did not alter tuber size distribution and the application of MCP reduced tuber size rather than increasing it. Results from this study suggest that both ethylene and MCP can be used in seed potato storage to influence the tuber size distribution of the crop from that seed.     

The effect of potato seed tuber age and soil temperature on the phenomenon of non-emergence

Summary In three experiments seed tubers of cvs Jaerla, Bintje and Alpha, stored at 12 °C in the dark, were planted in glasshouses on various dates at soil temperatures varying from 8 °C to 28 °C to study the phenomenon of ‘non-emergence’ with ageing seed tubers. In general the tubers were desprouted before planting. At all plantings cv. Alpha produced normal plants. The cvs Jaerla and Bintje, however, showed high proportions of the ‘little potato’ phenomenon when planted in cold soil, and high proportions of decayed tubers more frequently in warm soil. When using physiologically older seed at later planting dates, both the range of soil temperatures became wider and the proportions of seed tubers experiencing both ‘little potato’ and decay increased.     

Comparison of growth and yield parameters of Russet Burbank for a two-year period

The effect of three planting dates on stem, stolon, tuber number and size were compared throughout the 1979 and 1980 growing seasons. A relatively warm April and early May and a relatively cool late May and June in 1980 resulted in significantly higher stem and stolon numbers and a tuber population over double that of 1979. The highest average commercial yields ever recorded in the Columbia Basin were obtained with yields in some fields of 100 tons per ha on 48 hectare irrigation circles. On experimental plots tuber numbers increased from the latter part of May with successive sampling dates until late June and early July when a peak in number was reached after which a significant decline in number occurred. The decrease in tuber number was attributed to the phenomenon of reabsorption which was much greater with later planted potatoes. It occurred only in tubers of approximately 10 g size or smaller. Average tuber size in 1980 was one-half that of 1979 although total yield was 25 tons per ha higher because of significantly larger tuber numbers.     

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.     

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.     

不同播期对春大豆生态性状的影响

将来自北纬22.7°至北纬50.2°的19个春播大豆品种在2 a内分4期进行播种,研究了播期对不同生育期类型春大豆的形态和产量等生态性状的影响.结果表明:株高和主茎节数随着播期的延迟逐渐降低,并且降低幅度随着播期的延迟而增加.在各种熟期类型品种中,中早熟类型品种的株高和主茎节数降低的幅度最大.不同播期下大豆植株的地上生...     

Effect of whole seed tuber size and pre-plant storage conditions on yield and tuber size distribution of Russet Burbank

Field experiments were conducted in 1995, 1996, and 1997 at Agriculture and Agri-Food Canada’s Harrington Research Farm to assess the effect of whole seed tuber size and pre-plant seed storage conditions on processing yield (> 51 mm dia.) of potato (Solanum tuberosum L. cv Russet Burbank). Following commercial storage, seed tubers were stored at 4.4 C then subjected to one of three pre-plant treatments: (1) planted directly from storage, (2) held at 10 C for 3 wk before planting, or (3) green-sprouted for 3 wk before planting. Five sizes of whole seed were used (28, 42, 56, 70, and 84 g) with a variable size cut seed treatment added for comparison. Plots were harvested 138,134, and 131 days after planting in 1995, 1996, and 1997, respectively. Cut seed produced a higher yield of tubers > 51 mm diameter in comparison to all whole tuber seed sizes, with the exception of the 28 and 56 g sizes. In terms of total yield, the 28and 42-g whole seed tubers yielded significantly less than all other seed sizes examined. Warming or greensprouting seed tubers prior to planting did not increase tuber yield. The larger whole seed tuber sizes tended to result in greater numbers of stems and tubers per plant. To maximize marketable yield of Russet Burbank planted from whole seed tubers, it is recommended that the seed be between 28 and 42 g in size. Accepted for publication 25 May 2004.     

大豆不同品种类型对播期及密度的反应

选取结荚习性、分枝性不同的四个品种为试材,采用二因素最优化设计,进行了品种、播期、密度的综合试验,并建立了数学模型。 结果表明:各类型品种在同一地区种植均可获得高产,但需配有相应的最佳栽培模式;播期与密度对产量影响均较大。播期早晚主要影响花前期长短,进而影响产量。无限型品种适宜的密度较低且范围较窄;分枝性强的有限型品种,适宜密度较高,范围较宽;独秆型品种则要求密度高,范围最窄。产量与单位面积总荚数相关最为密切(r=0.934),每平方米总荚数高于700,可获得每亩高于150公斤的产量。     

不同品种及播期对丘区套作大豆产量的影响

在"麦/玉/豆"模式下,研究了不同品种与播期对丘区套作大豆产量的影响.结果表明,品种间产量差异极显著,以晚熟品种(贡选1号)的产量最高,达1375.11 kg/hm2,中熟品种(乐豆1号)次之,早熟品种(浙春3号)最低.与早中熟品种比较,晚熟品种表现为营养生长期较长,与玉米的生殖共生期为零,植株较高,茎粗增加0.13～0.16 cm,分枝多0.38～0.89个,主茎节数多4.47～7.12个,单株有效荚数、每荚粒数极显著高于早中熟品种,适合套作.播期间产量也有差异,以播期6月7日的产量最高.品种不同,表现略有差异.中晚熟品种的适宜播期为6月7日,表现为单株荚数、荚粒数较高;早熟品种以6月14日的产量较高,表现为单株荚数、荚粒数和百粒重较高.     

Potato planter performance and effects of non-uniform spacing

A survey of potato (Solanum tuberosum L.) plant stands in upstate New York over a three-year period showed that the average distance between plants was 4 cm wider than intended. Plant stands averaged 83%. The failure to plant seed pieces was the major reason for missing hills. Seed rot was not generally a problem, although one field in the survey was severely affected. Speed of planting up to 6.7 km/h had no consistent effect on average spacing or uniformity of seed piece distribution. Seed type (whole or cut) and mechanical condition of planter influenced spacing. Experiments conducted over four years indicated that the non-uniform seed piece distribution delivered by commercial picker-arm planters does not adversely affect crop yield or tuber size. Non-uniform seed distribution with extremely high coefficients of variation (greater than 100%), however, affected yield, tuber size and tuber number. Tuber numbers and yields were decreased by reducing the number of seed pieces planted per unit area whether or not the pieces were uniformly spaced.     

不同密度和种薯大小对产量及主要农艺性状的影响

为了明确在黑龙江省哈尔滨地区生态条件下，不同种植密度和不同种薯大小对马铃薯产量及主要农艺性状的影响，以密度为主处理，种薯大小为副处理进行了二因素裂区试验。供试材料为品种东农303。不同密度间，块茎数和总产有显著差异，两性状随密度的增加而增加。不同种善大小间，除净产量只达0．05显著水平外，其它性状均达0．01显著水平。株高、主茎数／每穴、块茎数随种薯大小的增大星线性增长，而总产、商品薯块茎数、商品薯产量、净产量随种薯大小的变化规律则只能用二次多项式来描述。采用新复极差法对各性状在不同密度及不同种薯大小下的表现作了多重比较。要想获得较高的商品薯产量及净产量，并考虑节约用种，提高繁殖倍数，在黑龙江省哈尔滨地区生态条件下，东农303的株行距应为30cm×70cm，种薯大小应为50～80g。     

The effect of temperature and light during storage of young seed potatoes on initial plant development at early plantings

Summary Young seed tubers of several cultivars were exposed to storage temperatures of 4–24°C in light and dark intended to optimise their growth vigour following early plantings. In five experiments during four autumn and winter periods, the effects of storage conditions on subsequent initial plant development in the glasshouse were studied. Storage of seed potatoes for 2 months at temperatures of 12°C or higher greatly increased early plant development of five cultivars following early plantings. Light during storage had a favourable effect, but desprouting before planting was greatly disadvantageous.     

Seed Potato Performance after Storage in Light at Elevated Temperatures

In regions with short growth seasons, it is of great importance to use potato (Solanum tuberosum L.) seed tubers with a high growth vigour and a short growth cycle. Such qualities may be obtained by treatments advancing the physiological age of the seed tubers. In this study, we have exposed tubers from four cultivars to various combinations of temperature and light conditions (green-sprouting) for 3–7 months in controlled climate. Subsequent sprout quality, seed tuber health and performance were studied in laboratory, greenhouse and field trials. Satisfactory short, sturdy and leafy sprouts were produced even after 7 months storage at 15 °C under light exposure. An assay of black scurf (Rhizoctonia solani) on the tuber skin showed that light exposure significantly reduced the occurrence compared with dark-stored tubers, while the average effect of storage temperatures was insignificant. In general, green-sprouting advanced emergence and plant growth by 1–2 weeks, and showed early tuber initiation and growth, compared to untreated material. Yields, 107 days after planting in the field trial, did not deviate significantly from untreated tubers. However, plant development at harvest was in accordance with general responses to physiological ageing of potato seed tubers, i.e. still tall and immature plants from untreated tubers, and short and mature plants from aged tubers. Results demonstrated the possibility of successful long-term storage of potato seed tubers in light at elevated temperatures and a potential for earlier harvests and higher early yields from such treatments.     

Effect of seed piece population on the yield and processing quality of Russet Burbank potatoes

The effect of seed piece population on tuber yield, size distribution and processing quality of Russet Burbank potatoes grown under nonirrigated conditions in southern Manitoba from 1983 to 1987 was determined. Seed pieces were planted at 21.7, 26.3, 33.3 and 45.5 thousand seed pieces per hectare, and plant emergence generally exceeded 90% of the seed piece population. Marketable tuber (greater than 5 cm in diameter) yields were not affected by seed piece population. As population increased, however, the number of harvested tubers increased and average tuber size decreased, which resulted in a decreased yield of premium tubers (greater than 284 g) and an increased yield of small tubers (less than 5.0 cm in diameter). Specific gravity, the incidence of hollow heart in maingrade (5 cm in diameter to 284 g in weight) and premium tubers, and fry color were not significantly affected by seed piece population. In the one trial tested, sucrose content decreased as population increased, however, this was not reflected in improved fry color after storage.     

Seed performance of Russet Burbank potatoes

A three-year study of three planting dates and four harvest dates of Russet Burbank seed potatoes was made to determine their effect on plant vigor, virus leaf roll infection, yield, size distribution and quality. Yields decreased significantly with delayed harvest of the seed crop. The incidence of late season virus leaf roll based on visual symptoms increased significantly with delayed harvests. The risk of a late season virus leaf roll infection increased when a later harvest was combined with a late planting. Seed taken from the earlier harvested plots consistently had earlier and more uniform emergence, the greatest vigor and the highest yields. The effect of planting date and harvest date had little effect on size distribution and no effect on specific gravity.     

How Planting Density Affects Number and Yield of Potato Minitubers in a Commercial Glasshouse Production System

Commercial potato minituber production systems aim at high tuber numbers per plant. This study investigated by which mechanisms planting density (25.0, 62.5 and 145.8 plants/m²) of in vitro derived plantlets affected minituber yield and minituber number per plantlet. Lowering planting density resulted in a slower increase in soil cover by the leaves and reduced the accumulated intercepted radiation (AIR). It initially also reduced light use efficiency (LUE) and harvest index, and thus tuber weights per m². At the commercial harvest 10 weeks after planting (WAP), LUE tended to be higher at lower densities. This compensated for the lower AIR and led to only slightly lower tuber yields. Lowering planting density increased tuber numbers per (planted) plantlet in all grades. It improved plantlet survival and increased stem numbers per plant. However, fewer stolons were produced per stem, whereas stolon numbers per plant were not affected. At lower densities, more tubers were initiated per stolon and the balance between initiation and later resorption of tubers was more favourable. Early interplant competition was thought to reduce the number of tubers initiated at higher densities, whereas later-occurring interplant competition resulted in a large fraction of the initiated tubers being resorbed at intermediate planting densities. At low planting densities, the high number of tubers initiated was also retained. Shortening of the production period could be considered at higher planting densities, because tuber number in the commercial grade > 9 mm did not increase any more after 6 WAP.     

Losses during Storage of Potato Varieties in Relation to Weather Conditions during the Vegetation Period and Temperatures during Long-Term Storage

Degradation of harvested tubers due to water loss, sprouting, and disease can cause severe economic difficulties in the cultivation of potatoes (Solanum tuberosum). This study evaluated the storage losses of new varieties of potato and determined the sprouting dates of potatoes stored at different temperatures. Additionally, this study evaluated the influence of weather conditions during the vegetative growth period on the date of sprouting in storage. After storage at three different temperatures (3, 5, and 8 °C), we estimated natural losses and losses caused by sprouting or the development of disease. The potato varieties stored at 3 °C, and 5 °C had similar weight losses (8.8% and 9.3%, respectively), but the potatoes stored at 8 °C had higher losses (10.8%). The average potato losses caused by disease ranged from 0.6% to 10%. The onset of sprouting of potatoes stored at 8 °C depended on the variety and began in the 20 day of December. Storage at 5 °C delayed sprouting by about 50 days compared with storage at 8 °C. Weather conditions (hot and rainy) during vegetative growth of the plants also influenced sprouting date, natural losses, and the amount of disease during storage. Our data showed a significant correlation between the hydrothermal coefficient during the vegetative period and the date of sprouting of potatoes during storage.     

Influencing seed tuber yield of Ranger Russet and Shepody potatoes with gibberellic acid

Freshly-cut seed pieces of the potato cultivars Ranger Russet and Shepody were dipped in 0, 0.5, 1 or 2 mg/1 Gibberellic Acid (GA₃) prior to planting. GA₃ treatments increased stem and tuber numbers per hill of both cultivars and shifted tuber size profile toward the production of more seed-sized (up to 226 g) tubers and fewer large (greater than 340 g) tubers. The effect of GA₃ on reducing average tuber size was similar for the two cultivars. Total tuber yields were not affected. A 2 mg GA₃/1 seed piece dip decreased the yield of US#1 tubers in Ranger Russet primarily due to a significant increase in yield of tubers less than 226 g. Also, yields of culls were greater after a 1 mg GA₃/1 seed piece treatment, suggesting Ranger Russet is sensitive to this concentration of GA₃. One and 2 mg GA₃/1 seed piece dips to Shepody increased yields of tubers less than 113 g by 93% and reduced the yield of tubers greater than 340 g by 25% to 50%. GA₃ at 1 to 2 mg/1 may be useful in the production of seed potatoes with the cultivar Shepody which tends to produce many large tubers.     

Effect of seed tuber and seed piece size on growth and incidence of hollow heart in Norgold Russet potatoes

Small seed pieces decreased yield and number of tubers. Both seed tuber and seed piece size affected the percentage of tubers with hollow heart. Hollow heart increased from 14 to 22% as the seed tuber size increased from 57 to 228 g and decreased from 27 to 19% as the seed piece size increased from 28 to 57 g. The least hollow heart (11%) occurred in tubers of plants grown from 57 g whole seed pieces and the most (26%) in tubers of plants grown from 228 g seed tubers cut into 28 g seed pieces. Hollow heart was positively correlated with the mean tuber size and negatively correlated with the number of mainstems per hill, total yield, and total number of tubers.