The development of pure homozygous lines is a critical objective in plant breeding, yet conventional methodologies for achieving this goal are time-consuming. Double haploid (DH) technology suggests a powerful technique for producing pure lines with homozygosity stabilization within a single generation. This study aimed to optimize haploid induction protocols and evaluated the effects of gamma-irradiated pollen (300, 400, 500 Gy, Co⁶⁰) on three cucumber (Cucumis sativus L.) genotypes (Dastjerdi, Beith Alpha, Super Dominus). Functional traits and pollen grain morphology, embryogenesis and fruit properties were evaluated under two pollination treatments (T1: simultaneous with irradiation; T2: one-day delay). The results showed that, dose of 300 Gy positively stimulated germination, pollen tube growth and haploid embryogenesis, while higher doses adversely affected pollen viability and wall thickness. Among the genotypes, ‘Dastjerdi’ exhibited superior tolerance to gamma radiation, likely attributable to its enhanced antioxidant capacity and efficient DNA repair mechanisms. Regarding pollination timing, simultaneous irradiation (T1) demonstrated higher efficacy compared to the delayed approach (T2). Strong positive correlations were identified between embryogenesis and pollen functional traits. No significant relationships were observed between pollen traits and fruit characteristics, indicating independent regulatory mechanisms. In conclusion, this study indicates that determining the optimal dose and correct pollination timing each genotype to improve DH production efficiency within cucumber breeding programs.
Abadi et al. (Thu,) studied this question.