Assessment of reproductive traits influencing breeding efficiency in chrysanthemum (Chrysanthemum morifolium Ramat.)

The study of reproductive biology, pollen morphology, and pollen viability is prerequisite for successful hybridization and the development of superior chrysanthemum cultivars. The present study examined the time and duration of anther dehiscence, stigma receptivity, pollen morphology, in-vitro pollen germination and pollen viability in diverse genotypes of chrysanthemum. Peak pollen dehiscence occurred during sunny hours between 11:00 AM and 1:30 PM across all genotypes, with the longest peak dehiscence period recorded in Pusa Aditya (2 h 30 min), followed by Flirt, Pusa Chitraksha, Pusa Shwet, Red Spoon, and Sensation (2 h 15 min). Moderate to high stigma receptivity (++; +++) of outer ray florets persisted for three days (4th − 6th days after emasculation) in Flirt, Pusa Shwet and Pusa Guldasta. Pollen morphological observations revealed grains were tricolporate with echinate exine ornamentation and categorized as oblate-spheroidal, spheroidal and prolate-spheroidal based on P/E ratio (0.96–1.06). Among different germination media, a combination of 15% sucrose and 15% PEG 4000 was found most effective for in vitro pollen germination. Red Spoon (45.64%), Lal Pari (45.10%), and Ragini (41.49%) exhibited the highest pollen germination. Pollen viability was assessed using 2,3,5-triphenyl tetrazolium chloride (TTC), Lugol’s solution and acetocarmine staining methods. Among these, TTC was found most effective, as these results are in close conformity with in-vitro pollen germination results. The integrated evaluation of reproductive traits identified Red Spoon, Pusa Aditya, Ragini, Flirt, Pusa Guldasta, Pusa Shwet, and Sensation as valuable parental resources for chrysanthemum breeding. These findings provide a scientific basis for selecting suitable parents, optimizing controlled pollination, and improving hybridization efficiency in conventional breeding programmes aimed at developing novel chrysanthemum hybrids.