Studies on floral biology of jasmine (Jasminum sp.) under northern dry zone of Karnataka

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Jasmine (Jasminum spp., family Oleaceae) is a commercially important flower crop valued for its aromatic blooms. Despite the wide genetic diversity present among jasmine genotypes, relatively few cultivars have been developed to date. Floral biology studies play a crucial role in identifying genotypes with favourable traits for breeding and crop improvement. However, such studies in jasmine are limited. So, the present investigation was conducted during 2019-2020 at the University of Horticultural Sciences, College of Horticulture, Bagalkot, Karnataka, to evaluate floral morphological and biological traits across 12 jasmine genotypes. Significant variation was observed in floral traits, including flower type, anthesis timing, anther dehiscence, stigma receptivity, and pollen sterility. The flowers were predominantly protandrous, with anther dehiscence occurring prior to anthesis. Anther dehiscence typically began at 4:00 PM and concluded by 7:00 PM, while anthesis commenced at 6:00 PM, peaking between 7:00 and 8:00 PM. Peak stigma receptivity was observed at anthesis and up to 12 hours post-anthesis. Most genotypes exhibited circular pollen grains, except J. multiflorum, which showed triangular pollen. Viable pollen diameter ranged from 42.57 to 79.53 ?m, whereas non-viable pollen ranged from 24.93 to 45.40 ?m. Pollen sterility percentages varied from 24.28% to 78.91%. This study provides essential insights into floral biology that can guide the selection of suitable parental genotypes for hybridization, helping to improve jasmine yield and quality. The observed variability in reproductive traits offers valuable information for breeders aiming to develop superior cultivars and can support strategic breeding and conservation programs in commercial jasmine cultivation.