EFFECT OF WATER STRESS ON MANGO FLOWERING IN LOW LATITUDE TROPICS OF NORTHERN AUSTRALIA

In the sub-tropics, night temperatures of 15°C or lower induce mango floral morphogenesis whereas temperatures of about 20°C or higher promote vegetative growth. In the tropics where temperatures may remain too high for induction of flowering by cool nights, a dry period preceding flowering is generally believed to be necessary for reliable mango flowering. However, the effect of the soil water deficit on flowering response is still a matter of controversy. Our studies, for the first time, examined the effect of soil water stress on flowering in mango trees grown under quasi-natural conditions (in open-air and in 200-litre drums) in the low latitude tropics. Controlled soil water deficit lasting 5 weeks was demonstrated to promote earlier and more intense flowering in mango trees of both ‘Kensington’ and ‘Irwin’ cultivars. Final fruit yield was also higher in water- stressed trees. Environment genotype effects on mango flowering were also discussed.