Manipulating flowering in mango, cv. Kensington pride

Kensington Pride is the predominant Australian mango cultivar but in warm, tropical conditions its productivity is low because of unreliable flowering and fruiting. Higher production and early fruit maturity are crucial to the viability of mango production in northern Australia. A project involving CSIRO, Northern Territory Department of Primary Industry and Fisheries (NTDPI&F), growers and Horticultural Research and Development Corporation (HRDC) was commenced in 1999 to evaluate two treatments with the potential to manipulate flowering and fruiting in Kensington Pride. The first treatment, applied only once at the outset, involved cutting a girdle around the trunk of the tree and applying the growth retardant, morphactin, by tying twine that had been soaked in a solution of the chemical into the girdle. The second treatment, applied annually after harvest, used paclobutrazol as a soil drench to inhibit gibberellin biosynthesis. These treatments were applied in twelve orchards around Darwin and Katherine. Effects on flowering, yield and quality were measured during 1999 and will continue until the end of 2001. The first year's data indicate that both treatments were successful in promoting earlier (by several weeks) and more intense flowering than controls. Overall, yields in the two treatments were about 50% greater than in controls but the size of the response in each treatment varied between sites. Data from the second and third years of the project will be required before firm recommendations can be made.