The Content of Total Carotenoids, Vitamin C and Antioxidant Properties of 65 Potato Cultivars Characterised under the European Project ECOBREED.

The aim of this study was to determine the effect of cultivars on the concentration of antioxidant compounds: total carotenoid content (TC) and vitamin C (VC), and their correlation with the total antioxidant activity (TAA) in 65 potato cultivars (Solanum tuberosum) from 10 countries. The TC content revealed a highly significant effect of the year (Y), cultivar (C) and flesh colour (FC). The TC ranged from 101.5 µg 100 g-1 DM (in cv. Kelly) to 715 µg 100 g-1 DM (in cv. Mayan Gold). The TC values were weakly correlated with years and higher in yellow-fleshed potatoes than in white-fleshed potatoes (319.9 vs. 175.6 µg 100 g-1 DM, respectively). The VC content ranged from 1.0 mg 100 g-1 FM (in cv. Bzura) to 14.8 mg 100 g-1 FM (in cv. Twinner). The content of VC were higher in yellow-fleshed (6.5 mg 100 g-1 FM) than in white-fleshed potatoes (5.8 mg 100 g-1 FM). The highest TAA were observed in cvs. Colleen, Basa, Triplo, Gatsby, Ditta, Twinner, Riviera, Michalina, Damaris, Belmonda, Ambo, Savinja, 12-LHI-6. For these cultivars, the FRAP values were 0.53 µmol TE 100 mg-1 DM and DPPH 0.55 µmol TE 100 mg-1 DM. The lowest TAA were observed in cvs.: Owacja, Mayan Gold, Kokra, Magnolia and Kelly. For them, the FRAP and DPPH values were slightly above 0.2 µmol TE 100 mg-1 DM. It was shown that the concentration of TC in potato tubers has an impact on TAA.

The relations of broad nematode resistance to quality characteristics as a consequence of marker-assisted selection in potato breeding programs.

Cultivating resistant varieties of potato is the most effective and environmentally sound method of protecting potato crops against pests and diseases. Potato cyst nematodes (PCN) are major nematode pests causing severe constraints in potato production worldwide. There are five pathotypes of Globodrea rostochiensis (Ro1-Ro5) and three of G. pallida Pa1-Pa3. Cultivation of potato varieties with broad nematode resistance may influence the growth of the wide spectrum of PCN pathotypes, but there is limited availability of such varieties on the market. The use of molecular markers allows for the effective selection of resistant genotypes at early stages of breeding. However, the impact of early selection for nematode resistance on the agronomic value of the final selected clones is a cause of concern for potato breeders. This study investigates the relationships between the presence of the combined resistance genes H1, Gro1-4 and GpaVvrn , which confer resistance to the nematodes, and certain agricultural traits. Clones with broad nematode resistance conferred by the genes H1, Gro1-4 and GpaVvrn presented yields and tuber morphology traits similar to those of the clones without identified resistance genes.

Quantitative trait loci analysis of potato tuber greening.

A conversion of amyloplasts into chloroplasts in the potato tuber after light exposure is known as tuber greening and is one of the major causes of tuber loss. We report here the first mapping of the factors affecting tuber greening in potato. We used an F1 mapping population of diploid potatoes and DArTseq™ markers to construct a genetic map. The individuals of the mapping population, parents and standards were phenotyped for two tuber greening parameters: external tuber greening and internal greening depth on 0-5 scales in three years 2015, 2016 and 2018. The results were used for the analysis of Quantitative Trait Loci (QTLs) by an interval QTL mapping. Two most important QTLs were covering large regions of chromosomes VII and X and had the strongest effect on both greening parameters in data sets obtained in particular years and in the mean data set. Variance observed in the mean tuber greening could be ascribed in 16.9% to the QTL on chromosome VII and in 23.4% to the QTL on chromosome X. The QTL on chromosome VII explained 13.1%, while the QTL on chromosome X explained up to 17.7% of the variance in the mean tuber greening depth. Additional, minor QTLs were year- and/or trait-specific. The QTLs on chromosomes VII and X determine big parts of the observed tuber greening variation and should be investigated further in order to identify the genes underlying their effects but also should be taken into account when selecting non-greening potato lines in the breeding process.

Antioxidant properties of potato tubers (Solanum tuberosum L.) as a consequence of genetic potential and growing conditions.

The concentrations of the bioactive compounds in potato tubers are determined by both genetic potential and environmental factors. The purpose of the experiment was to determine the influence of organic and integrated production on the expression of the genetic potential with respect to the antioxidant properties of potato tubers and to evaluate its stability under different environmental conditions. This phenotyping was performed on seven new breeding lines (tetraploid clones) and three modern cultivars: Jelly, Satina and Tajfun. The results indicated that production system and location significantly influenced the antioxidant capacity measured by FRAP method. Organic farming and the location Chwalowice were characterized by higher values. Furthermore, anitioxidative capacity measured by FRAP method was correlated with chlorogenic acid content (r = 0.590**) and glutathione fractions, especially with the reduced form (GSH, r = 0.692**). Multidimensional comparative analysis (MCA) proved a better development of antioxidant properties of potato tubers in the organic cultivation system when compared with the integrated. Especially favorable were growing conditions at Boguchwala (organic) and worst at Mlochów (integrated). From all investigated varieties, the best antioxidant properties were found in 'Satina' and 'Jelly'. Clones TG-97-403 and 13-VIII-45 developed the weakest health promoting traits.

Early selection of potato clones with resistance genes: the relationship between combined resistance and agronomical characteristics.

Cultivating resistant varieties of potato is the most effective and environmentally safe method of protecting against pests and diseases that affect potato crops. Therefore, potato breeding is focused on developing more resistant varieties so that the use of plant health products can be reduced during the cultivation cycle. Resistance to late blight, viruses and nematodes is the most important agricultural requirement. The use of molecular markers allows for the effective selection of resistant genotypes at early stages of breeding. However, the impact of early selection for resistance on the agronomic value of the final selected clones is a cause of concern for breeders. This study investigates the relationship between the presence of the combined resistance genes H1, Ry-fsto and Rpi-phu1, which confer resistance to nematodes, potato virus Y and late blight, respectively, and certain agricultural traits. The agronomic performance of most clones with and without the identified resistance genes was similar in terms of tuber yield, tuber size, tuber shape regularity, eye depth and tuber defect intensity. Some combinations with Ry-fsto may produce higher yields but may also be associated with more tuber defects. No negative relationships were observed between the combined resistance genes H1 + Ry-fsto + Rpi-phu1 and potato quality.