Shear press determinations of the raw product as a possible tool for quality measurement of potatoes

Texture determinations were made with a Food Technology Corporation shear press on Russet Burbank and Norgold tubers as they grew and developed from July 1 until October 15, 1970. Shear force reading increased as Russet Burbank tubers grew and increased in dry matter content. However, no increase in shear force was obtained with growth and development of the Norgold variety. Tubers harvested in the Fall were placed in 48 F storage and separated into specific gravity groups in increments of 0.005 with a brine solution. As specific gravity of the Russet Burbank variety increased, shear force readings also increased. Shear force of the Norgold Russet did not change with specific gravity changes. A very high correlation was obtained between raw shear force readings of specific gravity groups (Russet Burbank) and processed frozen french, fries of the same lots which were finish fried and shear force readings made within 3 minutes after removal from the fryer. Again, the correlation between raw shear force readings and finish fry readings of Norgold Russet was very poor, although the finish fry product readings increased as specific gravity increased.     

Physiological effects of psyllid (Paratrioza cockerelli) on potato

Feeding by psyllid nymphs causes “Psyllid yellows,” a characteristic yellowing of shoots which results in a dramatic loss of tuber yield. If psyllid infestation is not controlled, the onset of shoot yellowing and growth reductions can occur within two weeks. When insecticides are applied after yellowing, recovery of plants often is not complete. In this study comparisons were made of the physiology and growth of tops and tubers of recovered and permanently injured potatoes of the cultivars ‘Denali,’ ‘Kennebec,’ and ‘Norgold Russet.’ Permanently injured plants senesced rapidly, developed less shoot growth, aerial tubers and shortened and thickened internodes. They had lower tuber yields than plants that recovered. Permanently injured ‘Denali’ developed shoots on old flowering stems. In permanently injured plants of all cultivars, the tubers were small and badly misshapen but numbers increased. In recovered ‘Kennebec’ plants tubers were also misshapen, but were of average size. Tubers of recovered ‘Denali’ and ‘Norgold Russet’ were of acceptable shape. In samplings made during tuber growth, dry weight percentages of total soluble sugars, sucrose and glucose of tubers from permanently injured plants were found to be the same as those of recovered plants. In all cultivars, starch percentages of tubers from permanently injured plants were higher than that of the recovered, but the pattern of carbohydrate content changes was similar for permanently injured and recovered cultivars.     

Reinfection of potato seed stocks with potato virus S and potato virus X in Wisconsin

Reinfection of potato seed stocks with the potato viruses S (PVS) and X (PVX) varied with cultivar, virus, and grower. Rapid recontamination was observed for the cultivars Norgold Russet and Ontario with PVS and for the cultivars LaChipper, Norchip, and Norgold Russet with PVX. Recontamination was low for the cultivars LaChipper and Monona with PVS and for the cultivars Kennebec, Monona, Norland, and Superior with PVX. Survey results suggest that PVS and/or PVX can be eliminated from cultivars which appear to possess field resistance to infection, but that further evaluation of cultivars which are very susceptible to reinfection will be necessary.     

Norgold russet,superior and red la soda strains selected for potato cultivar improvement in Nebraska

Potato yield improvement in the United States has concentrated on cultural practices, disease eradication, and the development through breeding programs of new, disease-resistant, high yielding potato cultivars. Three strains of Norgold Russet—M, #35 and #19—have increased yields and vigor, and mature later than “regular” Norgold Russet. In trials conducted in Texas at Hereford (7 years), Olton (6 years) and Springlake (4 years), these strains have shown an average of 33, 29 and 20% increase in total yields, respectively. At Hermiston, Oregon (3 years), the mean total yield increases were 10, 17 and 12%, respectively. Strains M and #35 are more vigorous, and they mature 10 to 15 days later than Norgold Russet. Strain #19 is the most vigorous and upright of the strains; it matures 20 to 25 days later than regular Norgold Russet. Of all the Norgold Russet strains, strain M is the most popular. From Superior, a strain, New Superior, which matures 15 to 20 days later and is more vigorous, was selected. In Florida, New Superior’s yields averaged 26% greater than regular Superior but the specific gravity and chip color were not changed. Two strains of Red La Soda—#5 and #10—were selected for their earlier maturity. Strain #10 matures 7 to 10 days earlier than regular Red La Soda, and strain #5 matures 15 to 17 days earlier. However, these strains yield less. In Texas, at Olton (3 years) and Springlake (2 years), yields were reduced 23 and 34% for strains #10 and #5, respectively     

A plot design to sequentially harvest early generation selections and its use in evaluating fresh market characteristics of three new cultivars

A plot design was developed to compare changing yield and quality characteristics of early generation selections in our potato breeding program over a 6-wk harvest season. In this design all replicates for one harvest date are located within one row to facilitate harvesting and the variety plot arrangements in adjacent rows are identical to eliminate inter-variety plant competition effects. To illustrate the usefulness of this design, three new fresh market cultivars, Norkotah Russet, HiLite Russet, and Frontier Russet, and a standard commercial cultivar, Norgold Russet, were harvested every 10 to 14 days from late July through early September to measure earliness and optimum time of harvest for each cultivar. Each cultivar was found to have a characteristic maturation pattern. Total and marketable yields and tuber size distribution generally improved in all four cultivars as the harvest season progressed. However, the yield of marketable tubers of Norkotah and Frontier peaked and then decreased later in the season as many tubers became oversized (over 340 gms). Tuber number per plot was a stable attribute and was judged to be the most important factor determining performance of each line. Norkotah and Frontier produced fewer tubers and showed rapid tuber bulking and early production of marketable tubers of preferred sizes. HiLite produced more tubers than the other cultivars so had higher percentages of undersized tubers in late July and early August, but it produced high yields and desirable size distributions in late August and early September. Specific gravities for all three new cultivars decreased during early August, increased in mid-August as plants died, and then declined. HiLite and Frontier had higher solids than Norgold and Norkotah throughout the season.     

Methods to increase the starch content of potato tuber callus tissue

Summary Attempts were made to increase the starch content of callus tissue from tubers of cvs Lemhi Russet and Russet Burbank by varying growth regulator concentration, sugar source, sugar concentration, temperature and callus shape. Starch content was always higher in media containing no growth regulators. Callus spread over the media contained more starch than unbroken rectangular or cube-shaped callus. Sucrose was superior to glucose and fructose for starch formation. A sucrose concentration of 20 % produced more starch than lower concentrations. Callus growth decreased as the sucrose concentration increased. ‘Lemhi Russet’ callus incubated with 8 % sucrose at 20, 25 and 30 °C contained 1.2, 0.4 and 0.8 % starch respectively, which was much higher than in ‘Russet Burbank’ callus. With varying amounts of mannitol as an osmoticum in 8 % sucrose, the most starch was found in the medium containing 5 % mannitol. Research Paper 92B2 of the Idaho Agricultural Experiment Station     

Norgold Russet and Norgold Russet strain M — additional evidence for genetic dissimilarity

Potato improvement through strain selection has been under-exploited and sometimes discredited by plant breeders, even though successes, such as Russet Burbank, have been recognized. For years, seedsmen have rogued out “off-types” in order to maintain varietal purity. It is suggested that these off-types can sometimes offer an opportunity for developing improved strains or, depending on definition, improved varieties similar to the original variety, but possessing one or more unique characters which render it more acceptable or better adapted than the original variety. In Texas, Norgold Russet strain M, a selection out of Norgold Russet, is such an example. In this investigation, 2 genotypes, Norgold Russet and Norgold Russet strain M, were analyzed based on yield and plant attributes from 2 Texas sites over an 11-year period. Significant genotype x site, genotype x year, and genotype x site x year interactions were found, supporting the hypothesis that these 2 potato genotypes are phenotypically and presumably genetically dissimilar. Canonical discriminant analysis, using yield and plant attributes, confirmed these findings and provides additional evidence that varietal strains might deserve designation as unique varieties.     

Some factors influencing shear force determinations of Norgold Russet and Russet Burbank potatoes

Norgold Russet did not increase in shear force readings with growth and development as did the raw product of Russet Burbank which showed a progressive increase in readings with growth during the latter half of the season. Seasonal differences were apparent with Russet Burbank, but not for Norgold Russet during the 3 years of this study. Higher shear force readings were recorded with an increase of specific gravity of Russet Burbank, but not for Norgold Russet. Low fertility level resulted in slightly higher shear force values possibly because of enhanced maturity. No major influence of moisture stress was evident. Higher shear force values resulted from longer periods of storage and with higher storage temperatures of Russet Burbank within the range of 34F to 45F.     

High-efficiency regnerationin vitro from potato petioles with intact leaflets

The shoot/plantlet regenerationin vitro of seven potato (Solanum tuberosum L.) cultivars from petioles with intact leaflets was assessed using six treatment combinations-a basal medium with or without silver thiosul-phate (STS) or thidiazuron (TDZ) at two concentrations (2 or 0.5 mg/l) of the indoleacetic acid (IAA). The basal medium consisted of Murashige and Skoog (MS) salts and vitamins supplemented with 3 mg/1 6-benzylaminopurine, and 1 mg/1 gibberellic acid, 30 g/l sucrose, and 7.0 g/l PHYTOAGAR. Two full sets repeats and one partial set repeat of independent experiments were conducted and all produced similar results. Silver thiosulphate decreased the regeneration frequency and number of shoots per callus. No significant changes were observed with thidiazuron. Regeneration rates of (100% ) with up to 20 shoots/plantlets per callus were achieved at 2 mg/1 IAA with cultivars Désirée, Kennebec, Niska, and Lenape. These cultivars still showed high regeneration rates (87%–98% ) on media with 0.5 mg/1 IAA, and good regeneration rates were also achieved by the other three cultivars (48%, 94%, and 50% for Chieftain, Russet Burbank, and Shepody, respectively). Even with the single medium protocol (0.5% IAA without thiosulphate or thidiazuron), Désirée, Lenape, and Niska exhibited a regeneration rate of 98%. The use of petiole-with-leaflet explants could be ideal for the regeneration step of potato genetic transformation protocol because of their high regeneration efficiency and their small cut surface area forAgrobacterium elimination after co-incubation.     

Yield and relationships among tuber size,sucrose and chip color in six potato cultivars on various harvest dates

Cultivars were harvested biweekly for yield, weekly for sucrose determinations, and stored for chipping. At the last harvest Crystal was highest in total and marketable yield. Specific gravity was higher in Lemhi, Russet Burbank, and Norchip than in Kennebec, Crystal and Dakchip. Storage tests showed Norchip had superior chipping color to other cultivars. Dakchip had better color after short rather than after long-term storage, while the opposite was true for Kennebec and Russet Burbank. Lemhi and Crystal were marginal in color throughout storage. Sucrose (mg sucrose/g fresh tuber) expressed as a sucrose rating (SR) ranged from 1.2 to 11.9 among the various cultivars and harvest dates. Correlation between SR’s and tuber size within cultivars ranged from ?.91 to ?.97. Variability in sucrose content of immature tubers explained 70% of the variability in chip color among cultivars after storage from four to six months. Sucrose levels may be used to predict relative chipping quality of various cultivars after moderate to long-term storage if measured during early tuber development when differences in sucrose concentration are greatest among cultivars.     

Selection, evaluation, and identification of improved Russet Norkotah strains

Strain (sub-clonal, line, or intraclonal) selection for certain characteristics within some potato varieties has been very successful e.g. improved skin type (Russet Burbank from Burbank), improved skin color (Red LaSoda from LaSoda; Red Norland and Dark Red Norland from Norland), and improved vine vigor and yield (Norgold Russet M from Norgold Russet). In 1989, strain selection with Russet Norkotah was initiated by the Texas Potato Variety Development Program. Some 192 giant hill and/or tall type plants were selected from seedsmen and/or commercial Russet Norkotah fields in Colorado, while 183 were selected from commercial fields in Texas. Replicated yield trials with the final 13 of the original strain selections and Russet Norkotah were conducted in 1992, 1993, and 1994 in both Colorado and Texas. A mixed model analysis of variance was performed followed by disjoint cluster analysis in order to group strains into high, medium, and low yielding classes or clusters. Canonical discriminant analysis was performed to confirm the three clusters and to determine the extent to which various yield attributes are related and can be used to separate the three clusters. Several strains including TXNS (Texas Norkotah Strain) 112, TXNS 134, and TXNS 278 were identified as superior in Colorado, while TXNS 223, TXNS 249, and TXNS 296 were similarly identified for Texas growing conditions. These strains usually outyielded Russet Norkotah by 20–30%.     

Length of dormancy and sprouting characteristics of ten potato cultivars

The length of dormancy and sprouting characteristics of ten cultivars (Bison, Kennebec, Norchip, Norgold Russet, Norland, Red Pontiac, Russet Burbank, Viking, Dakchip, and ND8891-3), were compared. Russet Burbank had the longest dormancy period and the slowest rate of sprouting after dormancy ended. Viking and Norgold Russet had the most sprouts and Kennebec the fewest. Dakchip had the shortest dormancy period, the greatest weight of sprouts and the greatest weight loss. Dormancy was shortest in the warmest (20°C) storage. Storage at 2°C for six to nine weeks increased sprouting after dormancy ended compared with continuous 10 or 20°C storage.     

Electrophoretic characterization of North American potato cultivars

A total of 112 named cultivars and advanced breeding lines were assayed through horizontal starch electrophoresis to test the utility of isozyme loci as a means to objectively identify potato cultivars. Both leaf and tuber tissue were sampled in thirteen enzyme systems. Two buffer systems (Histidine-citrate, pH 5.7 and Lithium-borate, pH 8.3) were used to resolve 16 isozyme loci, of which 14 were scorable without progeny testing. A total of 43 scorable allozymes were detected. All cultivars or advanced breeding lines that were the result of hybridization were discriminated by their sum electrophoretic pattern, whereas, sports (i.e., Russet Burbank vs. Burbank) or line selections (i.e., Norgold Russet “M1” vs. “M2”) have patterns that are identical to the original mother clone. The allelic diversity within and among cultivars indicate that horizontal starch electrophoresis offers an objective means to discriminate sexually-derived potato cultivars.     

Identification of potato cultivars and clonal variants by random amplified polymorphic DNA analysis

Random Amplified Polymorphic DNAs (RAPDs) were used to distinguish commercial potato cultivars and clonal variants of cultivars. Primer 131, one of four primers used, distinguished 30 of the 36 cultivars tested. All 36 commercial cultivars were distinguished using only two primers (131 and 184). The RAPD pattern of 20 unidentified potato cultivars was compared with known patterns of 36 cultivars. Each one of the 20 cultivars was correctly identified. Particular primers appear to produce greater numbers of both amplified DNA fragments and polymorphisms, and are therefore suited to RAPD identification of potato cultivars. Polymorphism was obtained between Russet Burbank Idaho D and Russet Burbank White Skin with primer 251 and between Viking and Purple Viking with primer 380. However, polymorphism was not observed between Norgold, Norland, Sebago and Superior clones using only 20 primers. The RAPD technique is much more likely to detect polymorphism, regardless of tissue or environmental factors, than isozyme analysis and is easier, less costly and faster than the RFLP procedure. Thus, RAPD analysis represents a highly useful method of distinguishing and identifying potato cultivars and clonal variants of cultivars.     

Relationship of specific gravity to sugar accumulation in stored Norgold and Russet Burbank potatoes

Studies were made on the influence of growing season and low fertility on reducing sugar accumulation in storage of the stem and bud portions of Russet Burbank and Norgold Russet potatoes separated into different specific gravity groups. The stem portion of Russet Burbank had a significantly different intercept and slope of regression line (between specific gravity and reducing sugar accumulation) than the bud portions of the same tubers indicating higher reducing sugar accumulation in the stem portion as well as differences in behavior as to amount accumulated at the different specific gravity levels. No significant difference in sugar content or behavior at the different specific gravity levels was obtained between stem and bud portions of Norgold Russet. Growing season did not cause significant differences in total sugar content or slope of the regression lines within the stem or bud portions of Russet Burbank. Low fertility level resulted in significantly higher sugar accumulation in the stem portion of Russet Burbank as compared to adequate fertility and there was also a trend toward less influence of specific gravity on sugar accumulation at the lower fertility level. Low specific gravity Russet Burbank potatoes tended to be more variable in sugar accumulation from year to year and also had wider differences in sugar accumulation between stem and bud portions than high specific gravity potatoes.     

Responses of three early potato cultivars to subsoiling and irrigation regime on a sandy soil

A compact subsoil restricts rooting and reduces the volume of soil from which plant roots can obtain water and nutrients. A reduced water supply may result in severe plant water stress between irrigations. A study was conducted on a sandy soil to evaluate the responses of three early potato cultivars (Norgold Russet, HiLite Russet, and Russet Norkotah) to subsoiling to loosen a compact subsoil and to four irrigation regimes. Differences among cultivar responses to irrigation and subsoiling treatments were minor. All performed best with daily irrigation to replace évapotranspiration (ET) and poorest when irrigation was interrupted during tuber bulking. With daily irrigation to replace ET, subsoiling had little benefit, but with inadequate irrigation, subsoiling improved yield and quality of tubers compared to not subsoiling. Averaged over all treatments, HiLite was the lowest yielding cultivar and had the least U.S. No. 1 and the most undersize tubers. Norkotah had the most U.S. No. 1 and the fewest undersize tubers.     

Some factors influencing the pH of apical and basal portions of Russet Burbank and Norgold Russet potatoes

Studies were made of pH changes of apical and basal portions of Russet Burbank and Norgold Russet potatoes during growth and in storage. Russet Burbank had a higher pH of the apical portion during the later stages of growth as compared to the basal portion. No significant differences between the two portions were found during growth with Norgold Russet. After a period of moisture stress the pH of the basal portion of Russet Burbank dropped significantly. The basal portion of both varieties at higher specific gravities had higher pH after storage than the apical portion. A highly significant negative correlation was obtained after storage between reducing sugar levels of tubers of different specific gravities and pH levels in both varieties. There were no significant differences in pH among storage temperatures of 34, 38, 42 and 45 F. However, the pH level at 48 F storage was significantly higher than at the other temperatures. The pH level of tubers from seedlings and varieties were poorly correlated with their reducing sugar contents after storage. It appears that pH can be an indicator of potential chip color only within the confined limits of a specific lot.     

Lemhi Russet: A new high yielding potato variety with wide adaptation,attractive tubers,and high internal quality

Lemhi Russet, a new oblong, russet-skinned potato variety, was released by the U.S. Department of Agriculture and the Agricultural Experiment Stations of Idaho, Oregon, California, Washington, and North Dakota on September 23, 1980. The tubers of Lemhi Russet have been blockier, larger, 6% higher in solids, 50% lower in reducing sugars, and 25% higher in vitamin C than those of Russet Burbank. Lemhi Russet has averaged 34% more U.S. No. 1 tubers than Russet Burbank in 6 years of trials in five states. It was superior to Norgold Russet in yield and specific gravity in early harvest trials. In pilot plant and laboratory trials, Lemhi Russet made excellent french fries, baked well with a mealy texture, but sloughed when boiled. Lemhi Russet has a high degree of resistance to scab and net necrosis, but is susceptible to potato viruses S, X, Y, and to the leafroll virus. It is also susceptible to bruising and blackspot.     

苯乙酸促进水稻花药愈伤组织的再分化和直接成苗

 研究了苯乙酸（phenylacetic acid，PAA）应用于水稻花药培养的效果。以 2,4-D 为对照，发现PAA不影响愈伤组织诱导率，但显著提高了愈伤组织分化率（p<0. 05），从而显著提高了植株再生率（p<0. 05）。其促进效果与品种、培养基无机盐成分有关，对籼稻品种效果较好。PAA还能有效地促进花药愈伤组织不经转移到分化培养基上而直接在诱导培养基上分化成苗。直接再生的绿苗大多具有旺盛的不定根，可直接移栽到土壤中去。当PAA浓度为10 mg/L 时，特青、02428和亚优2号的直接植株再生率分别达0. 56%, 1. 64%和2. 69%。提高PAA浓度可进一步提高直接植株再生率。利用基于PAA的一步成苗培养法已构建成了3个水稻杂种花培后代加倍单倍体（DH）群体。     

Effect of antitranspirants on yield of Norgold Russet potatoes under greenhouse and field conditions

Antitranspirants (AT) were applied to greenhouse, field research plots and commercial plantings of Norgold Russet potato plants. In the greenhouse AT (Folicote and Vapor Gard) reduced water uptake by plants by 20–40%. In field trials at the Texas Agricultural Experiment Station, Halfway, similar concentrations increased yield of Norgold Russet potatoes by 21–45 cwts per acre (2352–5040 kg/ha). In a commercial trial on 20 acres of potatoes, 2% Folicote applied 5 and 3 weeks prior to vine kill increased total yield by 47 cwts per acre (5264 kg/ha) and increased yield of premium grade potatoes by 100%. Gross crop value at harvest was increased $500 per acre ($1125/ha). Significantly higher soil moisture levels existed in soils of treated plots between irrigations.