R. Coffin

Sodium sulphite inhibition of potato and cherry polyphenolics in nucleic acid extraction for virus detection by RT-PCR.

Phenolic compounds from plant tissues inhibit reverse transcription-polymerase chain reaction (RT-PCR). Multiple-step protocols using several additives to inhibit polyphenolic compounds during nucleic acid extraction are common, but time consuming and laborious. The current research highlights that the inclusion of 0.65 to 0.70% of sodium sulphite in the extraction buffer minimizes the pigmentation of nucleic acid extracts and improves the RT-PCR detection of Potato virus Y (PVY) and Potato leafroll virus (PLRV) in potato (Solanum tuberosum) tubers and Prune dwarf virus (PDV) and Prunus necrotic ringspot virus (PNRSV) in leaves and bark in the sweet cherry (Prunus avium) tree. Substituting sodium sulphite in the nucleic acid extraction buffer eliminated the use of proteinase K during extraction. Reagents phosphate buffered saline (PBS)-Tween 20 and polyvinylpyrrolidone (PVP) were also no longer required during RT or PCR phase. The resultant nucleic acid extracts were suitable for both duplex and multiplex RT-PCR. This simple and less expensive nucleic acid extraction protocol has proved very effective for potato cv. Russet Norkotah, which contains a high amount of polyphenolics. Comparing commercially available RNA extraction kits (Catrimox and RNeasy), the sodium sulphite based extraction protocol yielded two to three times higher amounts of RNA, while maintaining comparable virus detection by RT-PCR. The sodium sulphite based extraction protocol was equally effective in potato tubers, and in leaves and bark from the cherry tree.

The effect of light onin vitro microtuberization of potato cultivars

The effect of an 8 h light/day or total darkness photoperiod on thein vitro microtuberization of cultivars “Red Pontiac”, “Shepody”, “Kennebec” and “Yukon Gold” was investigated using a medium consisting of Murashige and Skoog salts, vitamins, high sucrose and high benzylamino purine levels and cultured at 16°C for 12 weeks. Percent tuberization of the singlenode leaf cuttings averaged over all 4 cultivars was initially lower, with the 8 h photoperiod at 4 weeks, but later was similar to the total darkness photoperiod at 8 and 12 weeks. Microtubers from all cultivars had a higher mean fresh weight when treated with an 8 h photoperiod as compared with total darkness, though the difference was not significant with “Yukon Gold.” ldRed Pontiac” and “Shepody” produced microtubers that were well over twice the fresh weight of those produced in the total darkness treatment. Delayed leaf senescence, microtuber greening, and nodal rooting were evident with the 8 h light treatment.

Potential for improvement by selection for reducing sugar content after cold storage for three potato populations.

The objectives of this study were to examine the expected response to selection for reducing-sugar content after cold storage in three hybrid populations, to determine whether these populations included clones low in reducing sugars, and to investigate the effectiveness of indirect selection for chip colour based on selection of sugar content after cold storage. The three hybrid populations included: a random sample of 39 clones of Population 1, which was derived from crossing ND860-2 (a clone low in reducing sugars) with F58089 (a clone intermediate in reducing sugars); 40 clones of Population 2, which was obtained from crossing ND860-2 with Russette (a clone high in reducing sugars); and 40 clones of Population 3, which was derived from crossing Russette with F58089. Sugar content and chip colour were assessed in tubers stored for 2 months at 4 °C at Cambridge, Ontario, and at 3 °C at Benton Ridge, New Brunswick. Population 1 had a slightly greater predicted response to selection for reduction in glucose and total reducing sugars than the other two populations. This could be attributed to higher heritability estimates for Population 1, which was a reflection of smaller clone × environment interaction mean squares. The greater potential advance by selection for fructose, glucose, and total reducing sugars, was a direct consequence of its lower means for these traits. Low reducing-sugar clones were found in all three populations, indicating their potential use for the selection of low reducing sugars. Populations 2 and 3, however, would require stronger selection pressures and, therefore, large population sizes. Expected correlated responses for chip colour by selection for fructose and glucose were similar to, and sometimes exceeded, the expected direct responses in all three populations. Indirect responses for chip colour by selection for sucrose, however, were lower than direct selection responses. These results indicate that indirect selection for chip colour, by selection for either fructose or glucose content after cold storage, is as effective as direct selection for chip colour.

Post-harvest Storage of Potatoes

Publisher Summary This chapter discusses the various factors that affect the quality of potatoes during post-harvest storage such as maturity stage of crop (early/late), intended use (table stock/processing/seed), preharvest conditions of crop, harvest and handling conditions, health of the crop such as incidence of pests and diseases, biochemical changes, storage preparations and conditions, and management of storage environment. The potato crop can be separated into late- or early-crop based on their maturity at harvest. Maturity is a complex physiological and morphological condition, which is influenced by several factors including respiration, carbohydrate changes, dry matter content, moisture loss, dormancy, and sprouting. The quality of the potato crop that is stored ultimately determines the quality of the stored product. A good storage management cannot enhance quality out of storage if the health of the tubers is compromised during preharvest conditions. Harvesting immature tubers, when the soil conditions are too wet or dry, and during too-warm weather conditions can affect the quality of tubers. Maintenance of post-harvest quality is critical for both growers and processors.

The effect of maleic hydrazide (potassium salt) on potato yield, sugar content and chip color of Kennebec and Norchip cultivars

A new formulation of maleic hydrazide (MH), a potassium salt formulation, was field tested for 3 years in Ontario to evaluate effects on yield performance, and on the sprouting and processing quality of cvs. Norchip and Kennebec potatoes. Foliar applied MH had no apparent effect on yield of potatoes, was effective in suppressing sprout growth, and had no effect on the sugar content (i.e., fructose, glucose and sucrose) of potatoes newly harvested and after 6 months storage. Although chip color varied from yearto-year, no consistent difference was found between the color of chips made from potatoes from untreated and MH-treated plants.

Inheritance patterns of reducing sugars in potato tubers after storage at 12 C and 4 C followed by reconditioning

Progenies from crosses of ND860-2, a low reducing sugar clone, with two potato cultivars (Trent and Onaway), differing in reducing sugar content, as well as the progenies of the parents selfed, were examined for reducing sugar content. Tubers were assessed after storage at 12 C for 10 weeks (regular storage) and 4 C for 10 weeks followed by reconditioning at 20 C for two weeks (reconditioning). After regular storage, all seedling progenies had relatively high frequencies of low reducing sugar segregates (i.e., equal or less than those of ND860-2 clone). After reconditioning, a high frequency of seedlings with low reducing sugars was observed in the progeny from ND860-2/Trent (46.7%), however, they were also found in the progeny from ND860-2/Onaway (6.7%). Results of this study suggested that progenies from crosses involving ND860-2 would segregate for low reducing sugar content regardless the reducing sugar level of the other parent.

Rose Gold: A yellow fleshed, pink-red skinned, tablestock cultivar with short dormancy and full season maturity

Rose Gold is a pink-red skinned, bright yellow fleshed, tablestock potato cultivar. In Ontario trials, Rose Gold is later maturing than its half sibling Red Gold and is characterized by producing larger and fewer tubers per plant than Red Gold. Rose Gold rarely develops symptoms of virus diseases when grown for repeated generations under high virus disease pressure (PVY, PLRV, PVX). Tubers have a very short dormancy. Yields are similar to Yukon Gold on mineral soil and generally higher than Red Gold. Rose Gold has produced high marketable yields on muck soil.CompendioRose Gold es un cultivar de papa para consumo de piel rosado-rojiza y carne de color amarillo intenso. En ensayos llevados a cabo en Ontario, Rose Gold madura más tardíamente que su medio hermana Red Gold y se caracteriza por producir por planta un menor número de tubérculos de mayor tamaño que la misma.Rose Gold rara vez desarrolla sintomas de enfermededes viróticas cuando se le utiliza por repetidas generaciones bajo una presión alta de dichas enfermedades (PVY, PLRV, PVX). Los tubérculos tienen un período de reposo muy corto. Los rendimientos son similares a los de Yukon Gold en suelo mineral y generalmente son más altos que los de Red Gold. Rose Gold ha producido altos rendimientos comerciables en suelo Muck.

Red Gold: A yellow-fleshed, red-skinned potato cultivar with short dormancy and high tuber set

Red Gold is a midseason maturity potato with pink-red skin and a bright yellow flesh. It is characterized by having a high set per plant of medium-small sized tubers. Marketable yields in Ontario, Canada are similar to or slightly less than Conestoga, Yukon Gold, and Superior. Boiling, baking, and field chip quality are acceptable with medium specific gravities (1.070–1.080). Short tuber dormancy makes this variety well adapted for whole seed tuber production for fall export markets. Red Gold has performed well in trials in Uruguay. Red Gold is moderately resistant to scab, field resistant to virus Y and leafroll, and susceptible to mild mosaic.CompendioRed Gold es una papa de madurez a media temporada con piel rojorosada y carne amarilla brillante. Se caracteriza por tener una gran formación de tubérculos de tamaño medio a pequeño, por planta. Los rendimientos comerciables en Ontario, Canada, son similares o ligeramente menores a los de Conestoga, Yukon Gold, y Superior. La calidad a la cocción, horneado y fritura es aceptable, con gravedades de término medio (1,070–1,080). El corto período de reposos de los tubérculos hace que esta variedad se adapte bien para la producción con tubérculos-semillas enteros, para los mercados de exportación en otoño. La performance de Red Gold ha sido buena en los ensayos de producción para mercados de exportación en otoño. Red Gold se ha comportado bien en ensayos en el Uruguay. Red Gold es moderadamente resistente a la sarna común, tiene resistencia de campo at PVY y al PLRV, y es susceptible al mosaico leve de la papa.

The concept and development of management profiles for potato cultivars and selections

Potato (Solanum tuberosum L.) growers in Ontario, Canada have funded research specifically to develop management profiles for potato cultivars. Such profiles have been developed for Atlantic, Conestoga, Jemseg, Monona, Norchip, Shepody, Superior and Yukon Gold grown under Ontario conditions.The development of management profiles to facilitate the optimum production and storage of different potato cultivars and selections is recognized as a valuable tool in aiding in the technology transfer of potato research and information to growers and processors.Unique differences among cultivars such as herbicide tolerance, time and duration of bulking, fertility requirements, processing quality and other variables may have significant impact on management of a particular cultivar. Some cultivar traits can be modified via management techniques while others cannot. A clarification of such information is critical to the industry.

Genetic advance for chip colour in potatoes

SummaryThe objective of this study was to investigate the response to selection for chip colour after harvest (CH), storage at 12.8°C (CR) and at 3°C (CC) in three hybrid populations. Population 1 was derived from crossing ND860-2 (cold chipper) with F58089 (regular chipper), Population 2 was obtained from crossing ND860-2 with Russette (nonchipper), and Population 3 was derived from crossing Russette with F58089. Eighty-five to ninety-six random clones for each population plus ten check cultivars were planted in 1991 at two locations in East Canada. For CH, Population 3 had the highest predicted gain. No genetic variation for this trait was detected in Population 1. The potential genetic advance by selection within Population 1, as measured by the predicted mean of the selected clones, however, was similar to the others because Population 1 has a higher mean. For CR, Populations 2 and 3 had similar expected response estimates. Population 1 had no genetic variation for CR but showed similar potential advance to Population 2 and higher than Population 3. For CC, Population 2 had the highest predicted gain. The predicted means of selected clones of Populations 1 and 2 were higher than that of Population 3. Consequently, Populations 1 and 2 had greater potential for improvement for CC than Population 3.