EFFECT OF TEMPERATURE ON POLLEN GERMINATION, POLLEN TUBE GROWTH AND SEED DEVELOPMENT IN MANGO (MANGIFERA INDICA L.)

The effect of constant and variable temperatures on pollen germination, pollen tube growth and seed development of ‘Nam Dok Mai’, ‘Kensington’, ‘Sensation’ and ‘Irwin’ mangoes was investigated. At 10°C, the average pollen germination for all cultivars was 53.9%. This increased to 76.2–77.4% between 15 and 25°C, and subsequently decreased to 68.2% at 30°C. The number of pollen tubes reaching the ovule in self-pollinated flowers of each cultivar was greatest at 20 and 25°C but declined at 30°C and was prevented when flowers were held at 10°C. \nLow temperatures, 20°C day/falling to 10°C night, 3 d after pollination significantly increased the percentage of stenospermocarpic (nubbin) fruit. There were significant differences between cultivars in the percentage of nubbins produced out of the total fruit set following low temperature exposure with 38.3% for ‘Nam Dok Mai’, 21.4% for ‘Kensington’ and 6.8% for ‘Irwin’. The lower percentage of nubbin fruit in ‘Irwin’ implies a greater adaptation to cool temperatures by this cultivar during fruit set and early development.