Hamed Ebrahimzadeh - Department of Tissue and Cell Culture, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
Mahmoud Lotfi - Department of Horticulture, College of Abouraihan, University of Tehran, Tehran, Iran
Mohammad Sadat-Hosseini - Department of Horticulture, Faculty of Agriculture, University of Jiroft, Jiroft, Iran

Doubled haploid method via parthenogenesis induction still remained prominent in Cucurbitaceae breeding due to drastic reduction in time and cost of newly released lines. In this study, different doses of Gamma ray (25, 50, 75, 100, and 200 Gy) were used to irradiate pollen grains for induction of parthenogenetic haploid embryos in oilseed pumpkin (Cucurbita pepo var. ‘Styriaca’). Parthenogenetic embryos at different developmental stages were rescued in vitro and 348 plants were obtained, of which 134 were recognized as haploid by ploidy analysis. The highest rate of haploid plants was obtained from globular (25.3%) and torpedo (23.8% plants) embryos followed by arrow-tip (13.4%), torpedo (10.5%), stick (10.5%), heart (9%), and cotyledonary (7.5%), respectively. All doses, except 200 Gy, were effective for induction of embryos and haploid plants; in a way that the highest number of haploids was obtained by 100 Gy. Our results indicated that parthenogenetic haploid embryos could be efficiently induced in C. pepo if proper Gamma ray dose and developmental stage of embryos are selected.

Breeding, Cucurbita pepo, Embryo rescue, hull-less pumpkin, medicinal plants, Oilseed pumpkin, Parthenogenesis