Varietal variations in temperature response for hermaphrodite flower production and fruit set in mango (Mangifera indica L)

• Varieties differ in the proportion of hermaphrodite flowers.
• Optimum temperature for maximum hermaphrodite flower proportion varies with varieties.
• Lower optimum temperature for north Indian varieties
• Hermaphrodite flower proportion is negatively related to the size of panicles.
• Temperature during floral initiation stage is determining the proportion of hermaphrodite flowers.

Mango produces hermaphrodite and staminate flowers on the same inflorescence and their ratio is influenced by genetic and environmental factors. Among the various environmental factors like temperature, rainfall, relative humidity, water stress and photoperiod, temperature is one of the most important factors influencing the production of hermaphrodite flowers. Therefore it is necessary to understand the influence of temperature in a locality on the flowering behaviour of different mango cultivars to select the most suitable type. To achieve this objective, the sex ratio of flowers (hermaphrodite/staminate) was recorded in panicles that emerged during the months of January, February and March and their relationship with mean minimum temperature during floral initiation stage was assessed for two years. Wide variability in flower sex ratio was observed among the cultivars and it ranged from 0.50 to 0.58 in cultivar Arka Aruna to 5.65 to 5.98 in cultivar Langra. The optimum, mean minimum temperature for maximum sex ratio in cultivars like Alphonso, Totapuri, Arka Aruna and Amrapali was 16.6 to 16.8 °C and in cultivars Langra and Kensington it was 15.5 to 15.7 °C. Fruit set was increased in the month of March followed by February in most of the cultivars indicating that the fruit set is influenced by both sex ratio and the higher temperature during flowering period.