MAIN FACTORS AFFECTING CUCUMBER (CUCUMIS-SATIVUS L) HAPLOID EMBRYO DEVELOPMENT AND HAPLOID PLANT CHARACTERISTICS

This report gives the first detailed analysis of cucumber haploid plan ts and the first evaluation of genotype and season effects on haploid embryo development. Female flowers of four Fl varieties and two inbred lines were pollinated with 300 Gy-treated pollen and three-week old e mbryos were cultured in vitro on E20A medium. The variety 'Polan' prod uced the greatest number of embryos (1.34 per 100 seeds), 51 % of whic h were capable of further development. The number of embryos able to d evelop was four times higher in summer than in spring. All the plants obtained, except one, were haploids or aneuhaploids. Haploid plants gr ew slowly and were sterile, although they occasionally set seedless fr uits. The length of the stems, leaves and guard cells was smaller than those of diploids.