American Journal of Potato Research最新文献

Potato mop top virus (PMTV) and Tobacco rattle virus (TRV) are significant soil borne pathogens of potato vectored by powdery scab and stubby-root nematodes, respectively. These viruses adversely impact tuber quality with infected tubers displaying brown streaks in the flesh and/or necrotic arcs on the surface contributing to the rejection of tubers in commercial settings. Currently, limited agricultural control methods for PMTV are available to farmers outside of planting resistant genotypes and avoiding fields with its vector; however, for TRV chemical control of the nematode vector is an option. Field screening for susceptibility to PMTV and TRV identified ‘Castle Russet’ to be resistant to both PMTV and TRV. In order to localize virus resistance genes for the development of marker assisted selection, a tetraploid mapping population (A15001) was developed by hybridizing ‘Castle Russet’ x A06084-1TE (susceptible to both viruses) and its progeny were subsequently trialed for two years in fields known to be infested with PMTV and TRV (two separate disease trial sites) near Larimore, ND. The population was phenotyped for PMTV and TRV incidence and severity of necrotic tubers at two time points post-harvest (approximately 19 days after harvest and 89 days after storage) with several genotypes in the population showing little or no virus induced necrosis over the years of evaluation, making them useful as parents in hybridizations by the potato breeding community. Tubers produced from the population were further assayed for PMTV and TRV infection by testing tuber core samples with a quantitative polymerase chain reaction (qPCR) assay. The A15001 population and the parents, 241 individuals, were genotyped with the Illumina Infinium SolCAP V2 12K Potato SNP Array yielding 6,704 quality-filtered, informative SNP markers. A genome wide association study (GWAS) analysis revealed SNP markers on multiple chromosomes (1, 2, 3, 5, and 11) that were significantly associated with PMTV incidence and negative qPCR suggesting polygenic inheritance. Conversely, GWAS revealed a significant QTL on chromosome 9 associated with all TRV phenotypes indicative of a major gene contributing to TRV resistance. These data can guide the development of molecular markers to select genotypes resistant to PMTV and TRV in potato breeding programs.

‘Rainier Russet’ was released in 2020 as a medium- to late-maturing selection with russeted tubers. Total yields are less, but similar to controls ‘Ranger Russet’ and ‘Russet Burbank’, and U.S. No. 1 yields are higher than Russet Burbank with increased tubers > 284 g. Compared to controls, it has high protein levels, high specific gravity, excellent fry color and flavor ratings, low acrylamide potential, good post-harvest merit scores for processing quality, and few internal and external tuber defects. Rainier Russet is susceptible to blight diseases, PVY, and Fusarium dry rot (F. solani var. sambucinum), but resistant to common scab (Streptomyces scabies) and Fusarium dry rot (F. solani var. coeruleum). Compared to Russet Burbank, tubers are less susceptible to hollow heart/brown center, secondary growth, growth cracks, and internal brown spot but higher tuber defects for net necrosis and shatter bruise with similar blackspot bruise potential. Rainier Russet is noted for its long tuber dormancy compared to Russet Burbank.

New, reliable strategies are needed to control Meloidogyne chitwoodi in potato; plant host resistance is central to this effort. While efforts to breed potato for resistance to M. chitwoodi are underway, a major bottleneck in this process is phenotyping plant genotypes for nematode resistance. Currently, time and resource consuming phenotyping takes place in the greenhouse or field. The objective of this study was to establish a high throughput methodology for screening potatoes against M. chitwoodi and quantify nematode egg densities at the end ofscreening using qPCR. Various parameters were evaluated for a canister assay where soil was added to a small container, planted with potato seed tuber, inoculated with nematode eggs, and incubated at a constant temperature in the dark. To obtain maximum reproduction factor (RF = final population density/initial population density) values, a minimum of 6 weeks after inoculation was required. Timing of inoculation was also important, with higher RF values when inoculation with eggs occurred at planting compared to 2 weeks after planting. The volume of water in which inoculum was delivered to soil did not impact RF values, nor did inoculation density (0.5, 1, or 5 eggs/g soil). The canister assay was evaluated using genotypes from a breeding population with varying levels of resistance to M. chitwoodi. Egg enumeration by qPCR was more sensitive than by microscopy, however, this increased sensitivity did not result in a significant difference in RF values nor the designation of a genotype being a good or poor host for M. chitwoodi. This method has the potential to greatly decrease the amount of time and resources needed to phenotype potato against M. chitwoodi and can allow for multiple screenings throughout the year, regardless of the season.

Nitrogen (N) fertilizer applied as polymer coated urea (PCU) may have the potential to improve potato (Solanum tuberosum L.) production. The objectives of this study were to determine the effects of PCU on potato yield and quality. ‘Russet Burbank’ potato was grown at three Idaho, USA locations. Five rates of N (0, 33, 67, 100, and 133% of the recommended rate) were applied in all combinations of: PCU applied at emergence, urea applied at emergence, or urea split-applied. The PCU-fertilized treatments produced 11%, 11%, and 10% higher US No. 1, marketable and total tuber yields, respectively, than urea-split applied. PCU trended toward increased tuber size. At equivalent rates, PCU was more efficient than urea N in providing N to potato. These results confirm findings from other researchers that a single application of PCU fertilizer, just prior to emergence, can efficiently meet seasonal N requirements for Russet Burbank potato.

Low soil moisture content and soil fertility are the major problems constraining productivity of potato (Solanum tuberosum L.) in the eastern highlands of Ethiopia. Therefore, a field experiment was conducted to investigate the effect of drip irrigation regimes and fertilizer rates on tuber yield, as well as nitrogen, phosphorus, and water use efficiencies of potato during the off-season of 2019/2020. The experiment was laid out as a split-plot design with three replications. Three levels of irrigation regimes, viz. 50%, 75% and 100% (full) of ETc were assigned to the main plots. Seven rates of fertilizer [control; 65 kg N + 242 kg NPS ha⁻¹(recommended rate); 50% of the recommended N + 75% of the recommended NPS along with 10 ton FYM ha⁻¹; 75% of the recommended N + 50% of the recommended NPS along with 10 ton FYM ha⁻¹; 75% of the recommended rate of N and NPS along with 5 ton FYM ha⁻¹; 75% of the recommended rate of N and NPS along with 10 ton FYM ha⁻¹ and 111 kg N + 92 kg P2O5 ha⁻¹] were assigned to the sub-plots. The results indicated that the optimum total tuber yield (48.38-ton ha⁻¹) and marketable tuber yield (47.80 ton ha⁻¹) were obtained in response to the application of 75% of the recommended rate of N and NPS along with 5 ton FYM ha⁻¹ together with 75% ETc. These total and marketable tuber yields exceeded the total and marketable tuber yield obtained in response to 50% ETc together with no fertilizer application by about four-fold. The above-mentioned treatment combination also resulted in the optimum agronomic nitrogen and phosphorus use efficiencies. Water use efficiency was improved by 3 kg m⁻³ in response to the application of 75% of the recommended rates of N and NPS along with 5-ton FYM ha⁻¹ together with 50% ETc compared to the same rate of the fertilizer treatment combined with 100% ETc. It is concluded that application of 75% ETc combined with 75% of the recommended rate of N and NPS along with 10 ton FYM ha⁻¹ increased potato yield, water productivity and N and P use efficiencies in Haramaya district.