Search

Copyright of American Journal of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mineral micro- and macronutrients in tubers of 21 Andean potato cultivars were investigated in a field trial under control and drought conditions. Mineral concentrations in potato tubers were highly variable between genotypes; some were significantly and positively correlated with each other, the most noteworthy associations being Na-Ca, Mn-Mg and Zn-Fe, in both control and drought-stressed plants. Overall, increasing yields are related to decreased concentrations of some nutrients, albeit some higher-yielding cultivars also displayed important concentrations of nutrients in their tubers. The most striking result was the increase in the concentration of the majority of the analysed cations in a large number of cultivars in response to water depletion; some of them, such as K, may be related to water homeostasis and/or to sucrose loading and unloading in phloem sap. Tuber mineral concentrations were not related to drought tolerance in terms of tuber productivity. Interestingly, yield loss under drought was not correlated with yield potential under control conditions. Identification of cultivars such as 703264 and 701106 able to maintain good yield stability in association with high mineral contents under water deprivation is of particular interest, especially in view of the importance of potato as a staple crop and the expansion of its cultivation to non-optimal cultivation areas in the context of changing climatic conditions. [ABSTRACT FROM AUTHOR]

Main and interaction effects of day-length and pathogen isolate on the reaction and expression of field resistance to Phytophthora infestans were analyzed in a sample of standard clones for partial resistance to potato late blight, and in the BCT mapping population derived from a backcross of Solanum berthaultii to Solanum tuberosum. Detached leaves from plants grown in field plots exposed to short- and long day-length conditions were independently inoculated with two P. infestans isolates and incubated in chambers under short- and long photoperiods, respectively. Lesion growth rate (LGR) was used for resistance assessment. Analysis of variance revealed a significant contribution of genotype × isolate × day-length interaction to variation in LGR indicating that field resistance of genotypes to foliar late blight under a given day-length depended on the infecting isolate. An allele segregating from S. berthaultii with opposite effects on foliar resistance to late blight under long- and short day-lengths, respectively, was identified at a quantitative trait locus (QTL) that mapped on chromosome 1. This allele was associated with positive (decreased resistance) and negative (increased resistance) additive effects on LGR, under short- and long day-length conditions, respectively. Disease progress on whole plants inoculated with the same isolate under field conditions validated the direction of its effect in short day-length regimes. The present study suggests the occurrence of an isolate-specific QTL that displays interaction with isolate behavior under contrasting environments, such as those with different day-lengths. This study highlights the importance of exposing genotypes to a highly variable population of the pathogen under contrasting environments when stability to late blight resistance is to be assessed or marker-assisted selection is attempted for the manipulation of quantitative resistance to late blight. [ABSTRACT FROM AUTHOR]

Major gene inheritance of resistance to Potato leafroll virus (PLRV) was demonstrated in a parthenogenic population derived from the highly resistant tetraploid a ndigena landrace, LOP-868. This major gene or chromosome region seems to control a single mechanism for resistance to infection and virus accumulation in this source. About 149 dihaploid lines segregated in a ratio of 107 resistant to 32 susceptible, fitting the expected ratio for inheritance of a duplex gene under random chromatid segregation. A tetraploid AFLP map was constructed using as reference the ultra high density (UHD) map. All AFLP markers associated with PLRV resistance mapped to the same linkage group. Map position was confirmed by analysis of previously-mapped SSR markers. Rl adg is located on the upper arm of chromosome V, at 1 cM from its most closely linked AFLP marker, E35M48.192. This marker will be used to develop allele-specific primers or a pair of flanking PCR-based markers for their use in marker assisted selection. [ABSTRACT FROM AUTHOR]

The cultivated potato, Solanum tuberosum, is affected by a variety of diseases with late blight, caused by Phytophthora infestans, being the most severe. Wild potato species have proven to be a continuing source of resistance, sometimes of an extreme type, to this disease. The present study constructs the first late blight linkage map of a member of series Piurana, S. paucissectum, a tuber-bearing relative of potato, using probes for conserved sequences from potato and tomato. Eight probes mapped to unexpected linkage groups, but syntenic differences with prior maps of potato were not supported by any blocks of rearranged chromosome segments. All 12 linkage groups were resolved and significant associations with late blight resistance were found on chromosomes 10, 11 and 12. A major quantitative trait locus (QTL) on chromosome 11 accounts for more than 25% of the phenotypic variance measured in a field trial. Crossing of S. paucissectum with cultivated potato resulted in very few seeds indicating partial reproductive barriers. Differential reactions of accessions of this potential donor species with simple and complex isolates of P. infestans suggest that it carries major resistance genes that are not those previously described from the Mexican species, S. demissum. However, the additivity of the QTL effects argues for the quantitative nature of resistance in this cross. [ABSTRACT FROM AUTHOR]

Characterization of nearly 1,000 cultivated potato accessions with simple sequence repeats (SSRs; also referred to as microsatellites) has allowed the identification of a reference set of SSR markers for accurate and efficient genotyping. In addition, 31 SSRs are reported here for a potato genetic map, including new map locations for 24 of them. A first criterion for this proposed reference set was ubiquity of the SSRs in the eight landrace cultivar groups of the potato, Solanum tuberosum. All SSRs tested in the present study displayed the same allele phenotypes and allele size range in the diverse germplasm set as in the advanced potato cultivar germplasm in which they were originally discovered. Thirteen of 13 SSR products from all cultivar groups are shown to cross-hybridize with the corresponding SSR product of the source cultivar to ascertain sequence homology. Other important SSR selection criteria are quality of amplification products, locus complexity, polymorphic index content, and well-dispersed location on a potato genetic map. Screening of 156 SSRs allowed the identification of a highly informative and user-friendly set comprising 18 SSR markers for use in characterization of potato genetic resources. In addition, we have identified true- and pseudo-multiplexing SSRs for even greater efficiency. [ABSTRACT FROM AUTHOR]

The CGIAR Research Program (CRP) on Roots, Tubers and Bananas (RTB) includes vegetatively propagated staple crops linked by common breeding, seed, and postharvest issues, and by the frequency with which women are involved in their production and use. RTB crops are the backbone of food security across the humid tropics in sub-Saharan Africa (SSA) and in more localized areas of Asia and Latin America. Around 300 million poor people in developing countries currently depend on RTB value chains for food security, nutrition and income. Climate change poses challenges which could undo progress in poverty reduction and markedly increase food insecurity. This article examines planning and research for climate resilience across RTB crops, with a particular focus on the contrasting potato and sweet potato cases in SSA. A six-step framework for climatesmart breeding is proposed: (1) downscaling climate change models and crop modeling; (2) identifying and understanding key climate change responsive traits; (3) breeding and varietal selection; (4) phenotyping and genomic research to accelerate gains; (5) developing management options for climate-smart varieties; and (6) deployment (seed systems). In summary, climate-smart breeding means we need to do what we already do but faster, better, and smarter.

Water deficiency has become a major issue for modern agriculture as its effects on crop yields and tuber quality have become more pronounced. Potato genotypes more tolerant to water shortages have been identified through assessment of yield and dry matter. In the present study, a combination of metabolite profiling and physiological/agronomical measurements has been used to explore complex system level responses to non-lethal water restriction. The metabolites identified were associated with physiological responses in three different plant tissues (leaf, root and tuber) of five different potato genotypes varying in susceptibility/tolerance to drought. This approach explored the potential of metabolite profiling as a tool to unravel sectors of metabolism that react to stress conditions and could mirror the changes in the plant physiology. The metabolite results showed different responses of the three plant tissues to the water deficit, resulting either in different levels of the metabolites detected or different metabolites expressed. The leaf material displayed the most changes to drought as reported in literature. The results highlighted genotype–specific signatures to water restriction over all three plant tissues suggesting that the genetics can predominate over the environmental conditions. This will have important implications for future breeding approaches. [ABSTRACT FROM AUTHOR]

Abstract: The ascorbic acid (AA) concentration of tubers was determined in 25 Andean potato varieties (Solanum tuberosum L.) grown in three environments, and the effect of cooking and storage time in subsets of samples was evaluated. Significant variation due to genotype, environment and genotype×environment (G×E) interaction was found. AA concentration in freshly harvested raw, peeled tubers ranged from 22.2 to 121.4mg/100g on a dry weight basis (DW) and from 6.5 to 36.9mg/100g on a fresh weight basis (FW) with the accession 704393 showing the highest levels of AA in all three locations. Differences in AA concentration were found among cooking methods and storage times; and significant non-crossover interactions with genotype were observed for both of these parameters. It was found that AA concentration of boiled tubers of the six varieties evaluated was higher than in oven and microwaved tubers and that AA concentration of tubers of the 23 varieties evaluated decreased with storage time. The variety 704393 retained 54 and 34% of its original AA concentration after boiling and storage during 26 weeks under farmer conditions. One hundred grams of fresh harvested boiled potatoes of this variety (704393) could provide adults with 17–20% of the recommended daily allowance (RDA) of AA. [Copyright &y& Elsevier]

Abstract: Samples from unprocessed and processed cooked tubers of the nine most abundant potato cultivars used to prepare the traditional freeze-dried food product, “chuño” in the central highlands of Peru were prepared and analyzed for their protein and mineral concentrations. The protein, iron, zinc and calcium concentration of cooked chuño of the nine cultivars evaluated ranged from 0.49 to 1.15g, from 0.29 to 0.65mg, from 0.04 to 0.14mg and from 18.9 to 31.0mg per 100g on a fresh weight basis, respectively. Potatoes processed as chuño have a lower concentration of protein and zinc than unprocessed tubers, and a higher content of calcium, while iron concentration may be expected not to be subjected to changes. Water used in preparing the chuño is suggested to be the cause for an increased calcium concentration in the final product, as the water used had higher calcium content before (1.35mequiv./l) than after (0.84mequiv./l) use in the preparation. Thus, water seems to be source of the increased calcium concentration. [Copyright &y& Elsevier]