In this study, three cultivars of potato and seven tetraploid breeding lines with different flesh colour were cultivated for three years at four locations in Poland. The objectives of this study were to quantify the levels of total (TC) and individual carotenoids (IC) and to determine the influence of genotype, farming system, growing location, years, and environment on the contents of these components. The aim of this study was also to identify genotypes with stable level of TC and IC. The mean total carotenoids content of tubers ranged between 5.57 and 20.20 mg kg −1 FW and was influenced by location, year, genotype, and their interactions. Mean values of lutein ranged from 2.92 to 6.66 mg kg −1 FWand zeaxanthin from 1.44 to 3.05 mg kg −1 FW. The most stable level of total carotenoids content was observed in tubers of breeding line TG-97-403. The most unstable level was found in tubers of cv. Jelly. The ranking of other genotypes depended on the used method. The presented study showed that the contents of carotenoids in potato tubers are significantly affected by environmental factors that cannot be controlled, because these are usually related to the year of cultivation. ResumenEn este estudio, se sembraron tres variedades de papa y siete líneas de mejoramiento tetraploides con diferente color de pulpa durante tres años en cuatro localidades en Polonia. Los objetivos de este estudio fueron cuantificar los niveles totales (TC) e individuales (IC) de carotenoides, y determinar la influencia del genotipo, sistema de cultivo, localidad, años, y el ambiente, en el contenido de estos componentes. La meta de este estudio también fue la de identificar genotipos con niveles estables de TC e IC. La media del contenido total de carotenoides de los tubérculos fluctuó entre 5.57 y 20.20 mg kg-1 de peso fresco y fue influenciada por la localidad, el año, el genotipo, y sus interacciones. Los valores medios de luteína variaron de 2.92 a 6.66 mg kg-1 en peso fresco, y la zeaxantina de 1.44 a 3.05 mg kg-1 de peso fresco. El nivel más estable del contenido de carotenoides totales se observó en tubérculos de la línea TG-97-403. El nivel mas inestable se encontró en tubérculos de la var. Jelly. Las cifras de otros genotipos dependieron del método usado. El presente estudio mostró que los contenidos de carotenoides en tubérculos de papa se afectan significativamente por factores ambientales que no pueden controlarse, porque generalmente están relacionados por el año de su cultivo.

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 Chwałowice 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 Boguchwała (organic) and worst at Młochów (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.

Potato cultivar Bzura bred in 1986 is one of the few European cultivars outstanding in high level of durable resistance to late blight, but its resistance has not been characterized. The presented study was aimed at clarifying bases of durable resistance in Bzura by testing its resistance and resistance in progeny individuals. In ten-year field experiment Bzura was significantly more resistant than mid-resistant standards Escort and Robijn, and only slightly less resistant than highly resistant Sárpo Mira. Bzura expressed also high resistance in detached leaflet tests when inoculated with specific isolates of Phytophthora infestans. It was found in Bzura progeny that this race-specific resistance segregated in 1:1 ratio and is governed by a major resistance gene R2-like. However, the long-lasting field resistance observed in Bzura could be explained by combination of R2-like gene and specific genetic background of this cultivar rather than by this gene exclusively.

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.

Photosynthetic properties and tuber yield were compared in seven tetraploid potato