Tillage Practices in Potato (Solanum tuberosum L.) Production: A Review

Potato is one of the main crops grown worldwide under different climatic conditions. Potato is conventionally produced under intensive tillage practices under the same or different soil types. Research has shown some contrasting effects of the tillage practices on the soil properties, crop growth, yield, and quality. Under the reducing available freshwater for food production, soil management practices are more targeting conservation and system sustainability. It is therefore critical to revisit literature on the tillage practices and their impact on the soil, crop, and crop yield. This review presents research results of studies conducted exclusively on potatoes comparing different types of tillage practices and is a valuable source of information for potato growers and scientists as it is not only focused on the impact of tillage practices on soil properties but also on potato tuber yield and grade, tuber specific gravity, and the impact of tillage practices on diseases in potatoes.

Efficiency of selection in early generations of potato families with a view toward heat tolerance

The aim of this study was to evaluate the efficiency of selection of potato families in early generations for heat tolerance. Thirty families were evaluated in the seedling generation (SG), first clonal generation (FCG) in the field and greenhouse under high temperature conditions, and second clonal generation (SCG) under mild temperatures. The mean of the families was obtained in each generation. The 16 most productive families in FCG were selected, and the clones of these families were evaluated in experiments in the winter and rainy crop seasons. The results showed that family selection for tuber shape may be applied as of the SG. It was also observed that family selection in the FCG and SCG for yield and tuber specific gravity contributed to identification of clones tolerant to heat and responsive to environmental improvement.

Cured Dairy Compost Influence on Weed Competition and on ‘Snowden' Potato Yield

Potatoes are an important global food crop typically produced in high-input systems in temperate zones. Growers that have access to compost may use it to improve soil health and increase tuber yields, but compost may also increase weed competition by increasing early-season water availability and weed growth. A field study at the Michigan State University Montcalm Research farm in 2010 and 2011 investigated the impact of compost on weed competition in potato. Potatoes were grown in field plots with 0, 4,000, or 8,000 kg carbon (C) ha−1of compost under weed-free conditions, and in competition with common lambsquarters, giant foxtail, and hairy nightshade. Compost did not increase biomass or seed production of any weed species. Giant foxtail and hairy nightshade at 5.3 plants per meter of row reduced potato yield by 20%; common lambsquarters reduced yield by 45%. The yield reduction by giant foxtail and hairy nightshade was due to a decrease in tuber bulking, whereas yield reductions from common lambsquarters were a result of lower tuber set and bulking. Potato yield increased 5 to 15% in compost compared to non-compost treatments; tuber specific gravity decreased by 0.3% in composted treatments. Across weed densities, elevated soil potassium levels in the 8,000 kg C ha−1composted treatment may have increased potato yield and decreased tuber specific gravity.

Genetic gains for heat tolerance in potato in three cycles of recurrent selection

Practically all potato cultivars grown in Brazil are native to Europe and not fully adapted to the tropical conditions. The purpose of this study was to estimate the genetic gains of three cycles of recurrent selection for heat tolerance in potato. The base population in this study consisted of five Brazilian and five heat-tolerant clones. In the winter of 2006 and rainy growing season of 2007 103 clones were evaluated (eight clones of the base population, 29 of the first cycle, 32 and 30 of the second and third recurrent selection cycle, respectively, and four control cultivars). The genetic gains for tuber traits in both growing seasons were 37.8 % (yield), 13.0 % (weight), 32.4 % (percent of large tubers), 0.8 % (tuber specific gravity) and 16.6 % (general tuber appearance). The percentage of physiological disorders (second-growth tubers and cracking) was also reduced by selection.

Sample size for family evaluation in potato breeding programs

Clonal families from a broad genetic base population in the Potato Breeding Program at the Universidade Federal de Lavras (UFLA), Brazil, were used in this trials. Twenty-five families were assessed in a 5 x 5 triple lattice design. Each plot consisted of 30 clones distributed in three rows of ten plants. Tuber yield per plant, percentage of large tubers, mean weight of large tubers, mean medium-sized tuber weight and tuber specific gravity were measured. Three hundred experiments were simulated varying the family sizes from three to 90 clones. The coefficients of experimental variation (CVe), the coefficients of genetic variation (CVg), heritabilities for family mean and the CVg/CVe ratio were estimated. Genetic parameters were stabilized with family sizes as small as six clones, depending on the trait. This indicates that the families can be adequately represented by a small sample of clones. Using the maximum curvature method it is possible to conclude that approximately 30 clones would be sufficient to represent each family, even for traits with the highest CVe. The genetic variance within family was greater than the genetic variance among families for all traits, indicating a favorable potential for within family selection. The correlation coefficients of the family means with the 5%, 10%, 15% and 20% best clones from each family, considering the five traits assessed, were always high, meaning that within the best families generally are the best clones.

Rate and timing of nitrogen fertilization of Russet Burbank potato: Yield and processing quality

Split fertilizer N application is thought to improve fertilizer N use efficiency of potato, primarily by reducing NO3 leaching losses. This study evaluated the effects of the rate and timing of N fertilization on yield and processing quality of Russet Burbank potato under rain-fed production. Trials conducted in 1999–2001 included different fertilizer N rates (0–160 kg N ha-1 in 1999 and 0–200 kg N ha-1 in 2000 and 2001) applied either at planting according to normal grower practice, or at hilling, the latest time that granular fertilizer can practically be applied. Tuber total and marketable yield, size distribution, specific gravity, fry colour and tuber concentrations of NO3, sucrose and glucose were measured. Increasing rates of N fertilization increased tuber yield and tuber size, increased tuber NO3 concentration and decreased tuber specific gravity, but had little effect on tuber sugar concentrations or fry colour. Season-to-season variations in total tuber yield responses to N fertilization rate were attributed primarily to variation in soil N supply. Timing of N application had little effect on tuber yield, size distribution or processing quality under adequate soil moisture conditions. However, under dry soil conditions, split N application reduced tuber yield and tuber size. Key words: Solanum tuberosum, tuber specific gravity, tuber nitrate concentration, fry colour

UCC-C4243 Dessication of Potato Vines

Chemical vine desiccation of potato (Solanum tuberosum L.) is widely used in the USA. Diquat is the major vine desiccant but has some drawbacks such as incomplete stem desiccation allowing regrowth. A new herbicide, UCC-C4243, was evaluated as a replacement for diquat. The potato cultivar `Atlantic' was treated with UCC-C4243 (a.i.) at 0.25 to 2.5 oz/acre (17.5 to 175 g·ha-1), and leaf and stem desiccation efficiency was compared to diquat (a.i.) at 4 oz/acre (280 g·ha-1). Split applications of UCC-C4243 were compared to double applications of diquat. Subjective evaluations were made on regrowth and tuber skinning, and objective measurements on specific gravity and yield. Trials were conducted from 1991 to 1995 at Scottsbluff, NE. UCC-C4243 at 1.5 oz/acre (105 g·ha-1) and higher significantly increased leaf and stem desiccation compared to diquat. There was no difference between single and split applications of UCC-C4243. UCC-C4243 suppressed regrowth at 1 oz/acre (70 g·ha-1) and prevented it at 2.5 oz/acre at 3 weeks after treatment while diquat did not. Skin set of tubers was promoted equally by all desiccants. Specific gravity was not lowered by UCC-C4243 but was by diquat. Yields were not affected by either UCC-C4243 at 1.5 oz/acre or diquat at 4 oz/acre. UCC-C4243 was more effective than diquat as a vine desiccant without the regrowth and tuber specific gravity effects associated with diquat.