Induction of haploid embryo and plant regeneration via irradiated pollen technique in pumpkin (Cucurbita moschata Duchesne ex. Poir)

Abstract

The effects of gamma ray doses (50, 100, 200 and 300 Gray) at different times (July 9, 11, 15, 21 and 28) on the obtention of gynogenic haploid embryo and plant regeneration via irradiated pollen technique were investigated in pumpkin (Cucurbita moschata Duchesne ex Poir.). Production of haploid embryo and plant increased significantly at the lower irradiation doses of C-60 (50 and 100 Gy) and earlier irradiation periods (July 9 and 11). Different forms and stages of embryos were extracted from the seeds. Production of haploid embryo and haploid plant were also strongly influenced by forms and stages of embryos, genotypes and harvest times. Haploid embryos and plants were obtained from only fruits pollinated with irradiated pollens at 50 Gy and 100 Gy and the highest parthenogenetic response was obtained from 50 Gy gamma ray doses. Frequency of haploid plant was 20% in torpedo and arrow-tip type embryos whereas cotyledon, hearth and amorphous type embryos produced only diploid plants. Necrotic embryos were the highest in delayed harvest times (5 and 6 week after pollination) and the best harvest time was determined about 3 weeks (between 18(th) and 24(th) days) after pollination. The frequency of haploid plants in per 100 seeds, 100 embryos and fruit were 0.24, 0.94 and 33.3%, respectively. The number of embryo per fruit was highest in "G9" (19.7) and "14YE02" (17.0) genotypes. Production of haploid embryo and plant was highest in the first (July 9) and second (July 11) irradiation times and 2 haploid plants were obtained.