EFFECTS OF LEAF - FRUIT RATIOS ON FRUIT-GROWTH, MINERAL CONCENTRATIONAND QUALITY OF MANGO (MANGIFERA-INDICA L. CV KENSINGTON-PRIDE)

To determine the effects of leaf:fruit ratios on growth, mineral conce ntration and quality of fruit, 30 uniform 'Kensington Pride' mango tre es had selected branches thinned to a single fruit and girdled to prov ide 30, 60 or 120 leaves per fruit. Control branches were not thinned or girdled and had on average 36 leaves per fruit. Decreasing the leaf :fruit ratio to 30 resulted in smaller fruit with lower dry matter (ge nerally an indication of fruit maturity), but extended the number of d ays to the stage of eating-soft at 22 degrees C (shelf life) by 2 d, i ncreased pulp Ca concentrations, and improved storage performance by r educing external chilling injury. Increasing the leaf:fruit ratio to 6 0 produced larger fruit and extended shelf life by approximately 2 d, but had no effect on dry matter or pulp Ca concentrations. A further i ncrease in the leaf:fruit ratio to 120 increased fruit size, dry matte r and the severity and incidence of disease but had no effect on shelf life or pulp Ca concentrations. Girdling had an independent effect on skin colour, with fruit from girdled branches having approximately 20 % less green and 5-12% more red blush on the skin at eating-soft. Gird ling also reduced the concentrations of Mg and K in the mango fruit pu lp. Percent dry matter and Ca concentration in fruit pulp had signific ant but weak, negative and positive correlations with fruit shelf life respectively, indicating that while both were involved in mango ripen ing, they were not the major determinants.