Perspectives of using interspecific hybridization for the improvement of oil pumpkins

Andreja Urbanek Krajnc (Maribor): The genetic breeders of oil pumpkin considered in their program numerous factors such as resistance against biotic stress, specific environmental conditions of production area, processing technology, as well as requirements of consumers and producers. The Styrian oil pumpkin (Cucurbita pepo L. var. styriaca Greb.) is economically the more important in the southern parts of Austria and the neighboring regions of Slovenia, Hungary, and Croatia. The major problems in its cultivation are viral diseases (especially the Zucchini yellow mosaic virus, ZYMV), extremely high temperatures, prolonged drought and occasionally pronounced wet periods, which may cause significant damage and severe economic losses. In our breeding program we used interspecific hybridization. We considered three crucial selection criteria: hull-less seed, bushy growth and light fruit exterior, in order to make oil pumkins tolerant to high levels of solar radiation and temperatures. Our study showed that some important chemical compounds dominate within seed coats (e.g., carotenoids, prochlorophyllides) and some in embryos (e.g., tocopherols, ascorbate and thiols). The variation ranges of most of the traits will enable breeders to conduct more rigorous selection aimed at the creation of highly productive and high quality cultivars, with the desired concentrations of antioxidants, especially tocopherols and pigments.