Özet:

Summer squash (Cucurbita pepo L.) is one of the important vegetable species preferred by the people of Turkey in terms of their nutritional value. F1 hybrid summer squash varieties are widely used both in the open field and protected cultivation. The majority of these varieties come from abroad, and our dependence on abroad continues. In this study, the effectiveness of the dihaploidization method, which has an important place in variety breeding studies, was investigated to reduce our import dependency and to produce new F1 hybrid varieties that are high yielded, quality, resistant to diseases and pests. In this context, 14 summer squash genotypes were used as plant material. Dihaploidization studies were carried out using the irradiated pollen technique. In total, 165 flowers were pollinated and 64 fruits, 7034 seeds, 521 embryos, and 144 plants were obtained. 111 pants were successfully acclimatized and cultivated in controlled conditions. As a result of ploidy analysis, 28 plants were haploid (2n=x=20), 77 were diploid (2n=2x=40) and 6 were mixoploid (containing diploid and haploid cells). Haploid plants were doubled with 1% olchicines treatment, grown in the greenhouse, selfed, and seeds were obtained.