Dry matter accumulation in potato clones under seasonal high temperature conditions in Pakistan

The effects of seasonal high temperatures on potatoes were investigated under field conditions near Peshawar, Pakistan. Five potato clones (A79196-1, Desiree, DTO-28, LT-1, Russet Burbank) were grown during the spring season at two locations. Canopy development, vine dry weight and tuber dry weight were determined at 13-day intervals, starting 68 days after planting (DAP). Tuber yield was higher in heat tolerant clones compared to heat susceptible clones. Location significantly affected tuber dry weights. Tuber dry weights of Russet Burbank were consistently lower than those of DTO-28. Ground canopy cover of DTO-28 occurred earlier and reached maximum at 75 DAP, compared to 90 DAP for Desiree. DTO-28, because of its high tuber yield under cool as well as hot temperatures, and its relatively early bulking, should be a promising clone for a short duration crop in hotter regions.     

Comparison of seasonal development of tuber specific gravity among seven potato clones

Specific gravity of potato tubers provides an estimate of starch content of which uniformly high levels are important for product quality. The objectives of this study were to document the relationship between the level of specific gravity and the variability among tubers and to model the seasonal development o f specific gravity for seven potato clones. Individual determinations were made on twenty tubers from each plot using the weight-in-air, weight-in-water method on each of eight harvest dates spanning the tuber growth period. For each plot, the mean and standard deviation of specific gravity were calculated and used to define the correlation between specific gravity level and tuber-to-tuber variability and to construct a predictive model of the seasonal specific gravity developmental pattern. As the season progressed, tuber-to-tuber variability of specific gravity increased for some clones but not for others. A positive correlation existed between tuber specific gravity mean and its standard deviation for four of the seven clones in 1991 and five in 1992. Correlation coefficients were generally low, suggesting only a weak association between specific gravity and its standard deviation. Tuber specific gravity developed in a similar seasonal pattern for the seven clones. It generally started low, reached a maximum approximately seven to eleven weeks after tuberset, at which time some clones showed a tendency to decline through the remainder of the season. Quadratic regression equations provided an adequate model to describe specific gravity development for all seven clones over the tuber growth period. Statistical contrasts were used to test for differences in equation parameters, including line coincidence, line slope, and intercept. The model showed that initial specific gravity level at tuber set, the rate of early season increase, as well as the length of time from tuber set to specific gravity maximum, varied by clone and determined the level of specific gravity at season’s end.     

Evaluation of potato clones for severity of Verticillium wilt, yield and specific gravity in Maine

In 1994 and 1995, the effect of Verticillium wilt, caused byVerticillium dahliae andV. albo-atrum, on tuber yields, number and weight of U.S. No. 1 and B size tubers, and specific gravity was studied in northern Maine, an area with a short growing season. Seven clones (four resistant and three susceptible) were evaluated in a split-plot design with three replications. Clones were the whole-plot factor, and seed pieces in sub-plots were either uninoculated or inoculated with 50 ml of 4 × 10⁴ cfu/mlVerticillium spp. at planting. Individual plants were scored for Verticillium wilt symptoms before harvest on a 1= <3% wilt to 10= >97% wilt. Differences among clones for wilting and specific gravity were significant. The inoculation treatment had no effect on any of the tuber traits measured. However, there were significant clone x inoculation interactions for most tuber traits. Reductions in yield, weight and number of U.S. No. 1 potatoes, and specific gravity were greater in the Verticillium wilt susceptible clones than in the resistant clones. These results suggest that breeding clones with resistance toVerticillium spp. will reduce yield losses, while maintaining tuber size and specific gravity under disease pressure.     

马铃薯杂交组合后代加工相关品质性状的评价

以马铃薯品种大西洋和东农303为母本的6个杂交组合的无性一代为试验材料,对其产量和加工相关品质性状进行评价。结果表明:综合表现最好的组合为大西洋×T1800,该组合产量高,平均单株产量可达604g;单薯重较高,平均单薯重可达80 g;高淀粉、低还原糖个体较多,后代中符合油炸加工类型的无性系比率最高。以东农303为母本的3个杂交组合后代比重偏低,但平均单株产量和平均单薯重均较高,可从这3个组合后代中筛选出高产鲜食的材料。     

Variance components for yield and specific gravity in a diploid potato population after two cycles of recurrent selection

The potato(Solanum tuberosum L.) processing industry needs cultivars with high tuber specific gravity and acceptable color of processed product. All of the cultivars with high specific gravity currently grown in the U.S. are very closely related, which increases their genetic vulnerability and results in inbreeding as efforts are made to improve these traits. The use of diploidSolanum sp. in breeding may resolve these problems. The purposes of this study were (1) to estimate narrow-sense heritability for yield and specific gravity in random-mating diploid hybrid potato populations ofS. phureja - S. stenotomum (PHU-STN) following two cycles of recurrent selection, (2) to examine phenotypic variances for yield and specific gravity following two cycles of recurrent selection within PHU-STN, (3) to compare the yield and specific gravity of individual PHU-STN clones with Atlantic, and (4) to screen these PHU-STN clones for the presence of 2n pollen. Four clones from each of 72 maternal half-sib families were evaluated for yield and specific gravity in replicated field tests in 1990 and 1991. A second selection cycle, using a randomly mated population obtained from the highest specific gravity clone in each maternal half-sib family, was similarly evaluated for yield and specific gravity in replicated field tests in 1995 and 1996. Narrow-sense heritability for specific gravity was estimated as 0.37 ± 0.25 and 0.43 ± 0.27, in the first and second selection cycles, respectively, with a 27% decrease in phenotypic variance. Narrow-sense heritability for yield was estimated as 0.60 ± 0.26 and 0.06 ± 0.24, in the first and second selection cycles, respectively, with a 73% decrease in phenotypic variance. There were significant correlations between yield and specific gravity in 1990 (r=0.32) and 1996 (r=0.37), but not 1991 (r=0.08) and 1995 (r=0.05). These results indicate that additional breeding efforts in this PHU-STN population could result in improvements in specific gravity. However, the amount of variation for yield in this population is decreasing and may indicate that the yield potential of this population is rapidly approaching its limit. In the second selection cycle, many of the 288 clones were significantly higher in specific gravity than the high-specific-gravity cultivar Atlantic, but none were higher yielding. Fifty-eight clones from the second selection cycle produced at least 5% 2n pollen. When used in tetraploid x diploid hybridizations, this diploid population could furnish new genetic material to the tetraploid potato germplasm base for simultaneously increasing specific gravity and yield.     

Use of canonical discriminant analysis in assessing the merit of crosses in terms of breeding goals

Canonical Discriminant Analysis was investigated as a means of assessing the merit of crosses in relation to established commercial cultivars and breeding goals. The progeny (30 per cross) of 22 crosses was evaluated in field plots at the Vauxhall Substation of the Lethbridge Research Station (Alberta). Mean values of the progeny of each cross for vine maturity, marketable yield, tuber size, tuber appearance and specific gravity were used to measure the overall merit of crosses in comparison to commercial cultivars. Breeding goals were established by calculating a 10% improvement in various combinations of the traits measured and then substituting these values in the canonical equations and computing theoretical values for the canonical variates. The canonical diagrams provided a precise and logical assessment of the relationship among cross means, control cultivars, and the breeding goals. Based on the evaluation of the 22 crosses, breeding goals for improvements in vine maturity, tuber size, marketable yield, and specific gravity over trait values obtained for Norchip and Russet Burbank, were realistic for the 1979 cross series but not for Norchip for 1980.     

Effect of seed production location on the performance of Russet Burbank clones in southern Australia

In this study, three clones of Russet Burbank were grown at five different seed production sites and one other clone was grown at three of these sites. Seed from these treatments was then evaluated at two commercial production sites, in Victoria and Tasmania. Production site had a significant effect on the subsequent performance. Plant establishment, vigor, maturity, and stem and tuber number per plant were influenced by seed production site. Seed from more southerly locations had increased plant emergence, greater early vigor, earlier maturity, and reduced stem and tuber numbers per plant. Differences between the Tasmanian, Ruen and Victorian Netted Gem clones were small and restricted to the numbers of stems and tubers produced, and some yield components. The Ballarat clone was late maturing and had a high total but low marketable yield due to high levels of oversized and misshapen tubers. However this clone also showed least dark end to the fried crisp. Interactions were detected between clone and seed production site but these have no practical significance.     

The relationship of cell size,intercellular space,and specific gravity to Bruise depth in potatoes

Cell size, specific gravity and intercellular space (IS) of 11 potato varieties were measured and compared with depth of bruising to determine if these factors are related to bruising. Rate of application of supplemental fertilizer did not change IS or tissue specific gravity. Variations in fertility level, moisture content of soil and temperatures during the periods of tuber growth and maturation caused only small differences in tissue specific gravity and IS. Depth of bruising, cell size, and IS differed among varieties. Analysis showed bruise susceptibility of tubers of different varieties was highest for tubers having low specific gravity, large cell size and high IS.     

Dakota Pearl: An attractive, bright white-skinned, cold-chipping cultivar with tablestock potential

Dakota Pearl (ND2676-10) is a medium-maturing chipping cultivar with uniform, round, bright white-skinned tubers with shallow eyes. Dakota Pearl has the ability to produce commercially acceptable chips following long-term storage at 5.5 C without the need for reconditioning. It yields well under both dryland and irrigated trial conditions in North Dakota. North Central Regional Potato Variety Trial and Snack Food Association Trial results indicate it has wide adaptability. Yield and specific gravity under dryland conditions are similar to Norchip; Dakota Pearl has a low percentage of external defects. Average set is 12 to 14 tubers per hill. Dakota Pearl demonstrates wide consumer appeal as a tablestock cultivar due to attractive tuber appearance and bright-white skin. Sensory evaluation scores for baking, boiling, and microwaving are comparable to those of standard chip cvs Atlantic, NorValley, and Snowden. The specific gravity of Dakota Pearl is similar to cvs Norchip and NorValley, lower than for Atlantic or Snowden. Total glycoalkaloid levels are low, at 1.5 mg/100 g fresh tuber tissue. The North Dakota Agricultural Experiment Station released Dakota Pearl on 23 April 1999.     

Influence of Source and Time of Potassium Application on Potato Growth,Yield, Economics and Crisp Quality

Field studies were conducted at the Central Potato Research Institute Campus, Modipuram (India), during two seasons (2003–2004 and 2004–2005), with two processing cultivars (cvs Kufri Chipsona-1 and Kufri Chipsona-2) and nine combinations of potassium source (K-chloride, K-sulphate and K-nitrate) and time of K application (basal dressing, split application and split application + foliar spray) to investigate their effect on tuber yield and processing attributes for crisp production under subtropical conditions. Yearly variations were observed for most of the variables studied. Between cultivars, the tuber and biomass yield was higher in cv. Kufri Chipsona-1, whereas specific gravity, tuber dry-matter percentage and crisp recovery were higher in cv. Kufri Chipsona-2. Stem number, plant height and compound leaf number were not influenced by sources of K fertilizer or application time. Processing-grade tuber yield, total tuber yield and biomass yield were statistically similar for K-chloride and K-sulphate and lower for K-nitrate. K sources affected both specific gravity and tuber dry-matter percentage significantly; K-sulphate and K-nitrate gave significantly higher values than K-chloride. The application time had no significant effect on processing grade and total tuber yield or on tuber specific gravity and dry-matter percentage. Values for crisp colour and reducing sugars were within the acceptable range for all treatments. Crisp yields were calculated to be highest and oil percentage of the crisps to be lowest when K-sulphate was applied as K fertilizer. Net income and benefit:cost ratio were highest for K-chloride followed by K-sulphate and lowest for K-nitrate. The study suggests that for crisping potatoes, K-sulphate is more suited than K-chloride, as it not only increased tuber dry-matter percentage and crisp yield, but also decreased crisp oil percentage.     

Growth analyses of eleven potato cultivars grown in the greenhouse under long photoperiods with and without heat stress

Six potato cultivars from North America were grown in two greenhouses under 18-h photoperiods. All plants were started in a greenhouse that was well ventilated and maintained as close as possible to summer ambient temperatures. One month after planting, half the plants of each cultivar were moved to a greenhouse that was kept at 30 C during the night and was allowed to reach 40 C or higher during the day. Plants from each treatment were harvested at monthly intervals for growth analyses. Concurrently, five clones considered to be heat tolerant were subjected to a similar test in a second experiment. In response to high temperatures, plants in both experiments were taller with smaller leaves, lower tuber yields, higher ratios of stem to leaf dry matter, and lower ratios of tuber to leaf and to stem dry matter. Tubers were lower in percent dry matter, maturity was delayed, and cuttings developed fewer tubers. Cultivars differed greatly in the degree to which they were affected by the heat. In the first experiment, Norchip had outstanding heat tolerance. LT-2 was the most tolerant of the clones in the second experiment. For the cooler treatment the best performance in either experiment was from two clones originally selected in the lowland tropics.     

Assessment of heat tolerance in potato (Solanum tuberosum ssp.tuberosum) under controlled environmental conditions: the ‘cutting technique’

Summary The ‘cutting technique’ or ‘tuberisation stimulus’ (TS) technique was investigated as a method of identifying heat tolerant clones ofSolanum tuberosum ssp.tuberosum. TS levels were assessed, using leaf cuttings, for 100 experimental clones growing under heat stress in a controlled environment (35/15°C day/night temperatures, 16 h photoperiod). No correlation was found with the tuber yields of these clones when grown in an irrigated trial in Israel. The relationship between TS levels and tuber production was investigated using early and later maturing cultivars grown with and without heat stress. These experiments showed that the cv. Blanka had high TS levels in all environments and high tuber fresh weights when grown under heat stress. However, the correlation between TS levels and tuber fresh weight for all cultivars was weak (r=0.45). The results indicated that this TS technique is unlikely to be an accurate method of screeningtuberosum clones for heat tolerance.     

Denali: A high dry matter potato with wide adaptation

Denali is a smooth, white-skinned potato bred and selected for high dry matter content early in tuber development at the Matanuska Research Farm. Its flavor is distinctive and pleasant as a baked potato. Chip quality has been excellent directly following harvest or from warm storage. In Michigan trials, Denali consistently has had the highest specific gravity and has been one of the highest yielders of approximately 20 varieties tested each year. Denali’s foliage has shown frost tolerance and heat resistance in tests conducted in Nebraska.     

Use of experimental tetraploids in potato breeding

High yielding experimental tetraploids from 4x × 2x crosses were found to be excellent parents, giving rise to many high yielding families and clones. Several of the progeny were found to yield over 900 cwt/acre at the Hancock Experimental Station. Both general and specific combining ability were significant for yield, while general combining ability was predominant for tuber appearance traits. Breeding methods to take both immediate advantage of the existing experimental tetraploids and to generate further experimental tetraploids that are of more desirable tuber appearance and possibly even higher yield are presented.     

Russette: A Russet-skin potato variety,combining high quality,high yields,and adaptation to the Northeastern states and Florida

Russette is a new, late maturing, russet potato variety adapted primarily for the northeastern United States and northern Florida. Tubers are oval to oblong, smooth with a medium-russet skin, and shallow eyes. Its specific gravity is similar to those of BelRus and Russet Burbank in areas of adaptation. Glycoalkaloid content is about 11 mg/100 g fresh weight. Baking quality is excellent, flesh is white, and best color of french fries is obtained from tubers stored at or above 13°C (55°F). Its long rest period makes it amenable to storage at a relatively high temperature before a chemical sprout inhibitor is needed. Russette is immune to virus A and leaf roll-induced tuber net necrosis; highly resistant to Verticillium wilt, tuber pinkeye, and tuber heat necrosis; and has good tolerance to scab, early blight, and Rhizoctonia infection of sprouts, stolon, and roots. Losses to rots and shrinkage in storage have been minimal. Russette is not resistant to viruses X, S, Y, and leaf roll and bacterial ring rot. Russette emerges to a stand about 10 days later than most varieties, however, subsequent vine growth is rapid until tuberization begins. Large-sized tubers may develop hollow heart under a late-season regime of high nitrogen and high moisture. A 22–30 cm (9″- to -12″) seed-piece spacing and 220 kg/ha (180 pounds/a) of nitrogen are recommended for production on mineral soils.     

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.     

Tuber initiation and development in irrigated and non-irrigated potatoes

Tuber initiation and development are processes basic to potato production and are particularly critical in areas with short growing seasons. It is important to know how and to what extent management decisions affect these processes in order to maximize the yield of marketable tubers. A two-year field study, conducted in southcentral Alaska, examined top growth, tuber initiation, and tuber development in eight potato cultivars grown with and without irrigation. Plants of the cultivars Allagash Russet, Bake-King, Green Mountain, Kennebec, Lemhi Russet, Russet Burbank, Shepody, and Superior were harvested weekly throughout the growing season, and top dry weight, numbers of tubers, and individual tuber fresh weights were recorded. Top dry weight was reduced by moisture stress shortly after emergence in 1993, and about one month following emergence in 1994, when early-season soil moisture was greater. The weight of tubers was similarly affected within approximately 5 wk of emergence in 1993 and 6 weeks in 1994. Tuber weight at harvest was increased two-to three-fold by irrigation in all cultivars. The number of tubers each plant set was affected by irrigation in most, but not all, cultivars. Some varieties (Lemhi Russet in 1994, Allagash Russet both years) set more tubers than were maintained through the growing season. Tuber remnants found during sample collection indicated that tuber reabsorption had occurred. Irrigated Green Mountain had more than one tuber initiation period during the season, whereas other varieties such as Shepody maintained a relatively constant number of tubers following initial tuber set. Tuber size distribution at the end of the growing season showed that larger tubers were favored by irrigation.     

Compatibility of potatoes to contrasting seasonal conditions,to high temperatures and to water deficit: The association with time of maturation and yield potential

Summary Genotypic variation in the adaptation of potatoes of several maturity classes to the specific climatological conditions of the autumn season, to the high summer temperatures and to water deficit, was studied. Late-maturing cultivars exhibited the highest yielding potential both in the spring and autumn seasons but specific compatibility of cultivars to the autumn was detected. The late-maturing cultivars were more susceptible to high temperatures than were the early ones. However, there were significant differences in susceptibility to high temperatures among cultivars of the same maturity class. Susceptibility to water deficit was similar in the various maturity classes, but there were differences in the susceptibility to drought among cultivars of the same maturity class. High yielding potential generally resulted also in acceptable tuber yields under conditions of water deficit. High temperatures in combination with a water deficit aggravated yield losses, especially in the late-maturing cultivars. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 2782-E, 1989 series.     

Protein,starch, and non-protein nitrogen accumulation in high protein hybrids and low protein cultivars

Tuber protein, starch, non-protein nitrogen and percent dry matter content were measured during tuber development of four Phureja-Tuberosum-Andigena hybrids and two Tuberosum cultivars. Percentages of starch and protein in the tuber dry matter were curvilinearly related to tuber size in all six clones. The amounts of starch and protein in a tuber were linear functions of tuber size. Rates of protein accumulation in some of the hybrids were higher than those of either cultivar. Starch accumulation rates were similar among all six clones. The high protein character of at least one of the hybrids was associated with starch containing storage tissue. Differences between high and low protein clones were mainly related to quantitative differences in the subunit composition of the protein. The ratio of non-protein nitrogen to protein N was similar among the six clones. Relationships between percent dry matter and starch content were not consistent among the six clones.     

Factors influencing time to breakdown (TTB) of cooked potato tissue

Cooking ability or time-to-breakdown (TTB) of different portions of potato tubers was determined by taking cores 1.27 cm (1/2inch) in diameter and 0.95 cm (3/8 inch) long from 12 locations in the tubers and cooking until penetration of a weighted rod pressing on the cores. Cores from the stem portion, on the average, required over twice as long for penetration of the rod during cooking as compared to cores from the bud section. The cores from the middle longitudinal portion of the tuber took longer to cook than cores from either side. Low specific gravity (1.070) tubers took significantly longer to cook than cores from high specific gravity (1.090) potatoes. However, when specific gravity of individual cores was determined with a pycnometer and TTB determined for the same samples, no relationships could be established. Cores from the stem portion took longer for TTB regardless of specific gravity or starch content. The data suggested much greater influence of cell wall structure as would be obtained from different portions of the tuber on TTB than starch content of the cells. No differences in TTB were obtained from tubers of high or low fertility or between Norgold Russet and Russet Burbank varieties, except Norgold was more uniform in cooking time between the stem and bud portion than Russet Burbank.