Study of floral biology in different varieties of Gladiolus in the foothills of Himalaya

The present study was conducted during 2023-2024 at the Model Floriculture Centre and the College of Agriculture, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, to elucidate the floral biology of nine Gladiolus varieties to inform breeding strategies, particularly hybridization programs. Significant genotypic variations were observed across key reproductive parameters. The duration of anthesis ranged from 3.56 h in Nathan Red to 8.18 h in Acidanthera. Anther dehiscence commenced post-anthesis, with durations spanning from 2.48 h in Bindiya to 8.23 h in Acidanthera. Stigma receptivity initiated after anther dehiscence, persisting for 43.70 h in Careless and extending up to 60.45 h in Vicky Liar. Morphometric analyses of reproductive structures revealed significant differences among the cultivars. Vicky Liar exhibited the longest androecium (5.38 cm), whereas Careless had the shortest (3.49 cm). Filament lengths varied from 3.03 cm in Careless to 4.67 cm in Bindiya. Anther length ranged between 0.82 cm in Purple Majesty and 1.66 cm in Acidanthera. Gynoecium lengths were shortest in Purple Majesty (7.09 cm) and longest in Acidanthera (15.93 cm). Style lengths spanned from 4.57 cm in Careless to 7.66 cm in White Prosperity. Stigma lobe lengths varied, with Bindiya at 0.54 cm and Careless at 1.83 cm. Pollen viability exceeded 50% across all varieties, peaking at 67.15% in Acidanthera and reaching a minimum of 58.62% in Careless. Pollen size measurements indicated the largest grains in White Prosperity and Punjab Morning and the smallest in Bindiya and Regency. These findings underscore the genetic diversity among the studied Gladiolus cultivars, highlighting the necessity of comprehensive floral biology assessments prior to initiating hybridization programs. Such evaluations are critical for selecting optimal parental combinations and timing pollination to enhance seed set success.