Induction of haploid in chrysanthemum via irradiated pollen induced parthenogenesis.

Induction of gynogenesis through parthenogenesis is an important approach for the development of haploids in horticultural crops. To our knowledge, this is among the first reports of regeneration of tri-haploids through pollination with irradiated pollen in chrysanthemum (Chrysanthemum × morifolium). The objective of the study was to evaluate the effects of different doses of gamma irradiation on pollen viability, pollen germination, and the frequency of gynogenic tri-haploid induction. Two chrysanthemum cultivars, ‘Pusa Centenary’ and ‘Star White’, were used as female parents, while ‘Pusa Aditya’ served as the pollen source. Flower buds were exposed to different doses of gamma irradiation (50, 100, 200, 300, and 400 Gy) followed by pollination of the female parents. Irradiation doses of 200 and 300 Gy resulted in recovery of tri-haploid plantlets. The ploidy level of regenerated plantlets was determined by counting chloroplast numbers in stomatal guard cells and through flow cytometry analysis. Among the total plantlets analysed, 10.71% were characterized as tri-haploids, while 89.28% were hexaploids. The present study highlights the potential of gamma irradiation as an effective method for inducing gynogenic haploids, which may be valuable for future chrysanthemum breeding programs.