Progress in the production of haploid embryos, plants and doubled haploids in cucumber (c. sativus l.) by gamma irradiated pollen, in turkey

Parthenogenetic haploid embryos in situ were induced following pollination with gamma-irradiated pollen. The embryos were rescued and cultured in vitro giving rise to haploid plantlets which when treated with colchicine resulted in cucumber plants with doubled chromosome number, so called doubled haploids. The study was carried out between 1991 and 1996. After having managed the production of haploid embryos, haploid plants and doubled haploids, it was decided that the effect of the irradiation doses, timing of pollination and maternal effect on the frequency of haploids induced be studied in more detail. The most suitable period of time for pollination was determined to be between May and September under the climatical conditions of Mediteranean Costal Region of Turkey. When tested on 27 different genotypes, the highest frequency of haploids were induced by low doses of irradiation (200, 300Gy), expressing genotypic independence. The haploid embryos readily germinated on the E20A medium, becoming haploid plantlets which then were multiplied by cuttings. The chromosome number of haploid plantlets were doubled by colchicine treatment in vitro, after which presumably doubled plantlets were acclimatized, transferred to soil and grown under greenhouse conditions. Finally the seeds were obtained from the doubled haploid cucumber plants. A one year working calendar is developed and presented for all these processes to obtain doubled haploid cucumber lines