Effect of cincturing and chemical treatments on growth, flowering and yield of mango (Mangifera indica L.) cv. Kensington Pride

Summary. Mango (Mangifera indica cv. Kensington Pride) is the main horticultural tree crop grown in the tropical regions of northern Australia. A major problem for growers is that flowering and fruiting of this cultivar is highly variable from year to year. A series of field experiments was conducted to evaluate cincturing and chemical treatments as a means of improving mango productivity. A standard cincture (Cincture) was compared with a modified technique in which twine was tied tightly into a cincture groove (Twine). The chemical treatment was based on a morphactin formulation (MF) and was introduced to the trees by either painting directly onto the bark of the tree trunk (MF-paint) or soaking twine in MF before tying it into a trunk cincture (MF-twine). The amount of morphactin applied varied with tree age and was in the range from 0–0.06 g active ingredient (a.i.) per tree. Tree responses, measured in terms of vegetative growth, flowering and fruiting, were compared with trees that had been treated with a physical cincture only, or with paclobutrazol (up to 5.0 g a.i.), applied as a collar drench. In young (3–8-year-old) trees, Twine, MF-twine and MF-paint had a positive effect on flowering and fruiting. These trees had earlier, more intense flowering, produced early (September) maturing fruit (up to about 4-fold increase) and had high fruit production (up to about 2-fold increase in fruit number) compared with controls. In some cases vegetative growth was reduced by 50–60% compared with untreated trees. Twine and MF-twine are favoured over MF-paint because (i) the paint must be applied annually, incurring high labour costs, and (ii) paint treatments carry the risk of overdosing the trees with morphactin. The positive effects of Twine and MF-twine treatments were sustained, with large responses in flowering and/or fruiting 2–4 years after application. The responses in fruit production from paclobutrazol, applied at rates based on manufacturer’s recommendations, were less than with Twine, MF-twine or MF-paint.