Citrus is one of the most commercially important fruit crops globally, with reproductive efficiency and floral traits playing a crucial role in determining yield potential and suitability for hybridization. This study aimed to evaluate the floral morphology, flowering phenology and pollen viability of seven citrus cultivars: three mandarins ('Kinnow', 'Daisy', 'W. Murcott') and four sweet oranges ('Blood Red Malta', 'Jaffa', 'Mosambi', 'Valencia Late'), under subtropical conditions of Hamirpur, Himachal Pradesh. The experiment was conducted during 2019-2021 using four replications per cultivar in an Ultra High-Density Plantation system. Floral traits were recorded following IPGRI descriptors, while pollen viability was assessed using 2% acetocarmine stain. Significant genotypic variability was observed in flower size, filament and style length and pollen fertility. 'Mosambi' exhibited the largest flowers, whereas 'Kinnow' recorded the highest proportion of perfect flowers (93.50%) and pollen viability (92.50%). In contrast, 'Valencia Late' and 'Blood Red Malta' had higher percentages of staminate flowers, potentially limiting their pollination efficiency. The results highlight the genetic diversity among cultivars and underscore the importance of floral traits in breeding and orchard planning. Cultivars like 'Kinnow' and 'Mosambi' may serve as superior pollen parents in citrus breeding improvement programmes targeting enhanced fruit set and productivity.

Citrus, Floral Morphology, Phenology, Pollen Viability, Acetocarmine Variability

This study highlighted genotypic variation in floral morphology, flowering phenology and pollen viability among seven citrus cultivars evaluated under subtropical conditions of Hamirpur, Himachal Pradesh. Differences in flower size, filament and style length reflected the cultivars' genetic diversity. Larger floral structures in cultivars like 'Mosambi' and 'Valencia Late' may enhance pollinator attraction and facilitate better fruit set. 'Kinnow', with the highest percentage of perfect flowers (93.50%) and pollen viability (92.50%), showed superior reproductive efficiency. Conversely, 'Valencia Late' and 'Blood Red Malta' had higher proportions of staminate flowers, which may reduce their effectiveness in natural pollination. These findings highlight the importance of floral characteristics and pollen fertility in determining fruit set, yield potential and breeding value of citrus cultivars

Shivali Chauhan, Vikas Kumar Sharma, Rupam Nehta, Lakesh Rahi, M.A. Kuchay and Sanjeev (2025). Genotypic Variability in Floral Morphology, Flowering Phenology and Pollen Viability of Citrus Cultivars under Subtropical Conditions. Biological Forum, 17(5a): 107-110.