Effect of bunch trimming and leaf removal at flowering on maturity bronzing, yield, and other aspects of fruit quality of bananas in North Queensland

Abstract

This study examined the effects of bunch trimming and leaf removal on rate of bunch filling, severity of the maturity bronzing fruit peel disorder, and other yield and quality paramaters. There were 4 levels of leaf removal (4, 7, 10, 13 leaves retained) and 4 levels of bunch trimming (male bud retained, male bud removed, male bud and 2 hands removed, male bud and 4 hands removed) imposed on banana bunches at flowering. The experiment was carried out at South Johnstone, North Queensland. The 320 plants in the trial produced a range of fruit-filling rates that were largely unrelated to the imposed treatments. With the exception of the duration of fruit filling and extra large fruit weight, leaf removal and bunch trimming acted independently on the attributes measured. Leaf removal reduced maturity bronzing and bunch trimming increased it. Increased bronzing was associated with increased finger length, possibly due to epidermal cells in the fruit peel elongating beyond their elastic limit. Bunch trimming reduced bunch weight and but did not improve the quantity of extra large fruit. Leaf removal reduced bunch weight when <10 leaves remained, due largely to a reduction in finger length throughout the bunch. Fruit greenlife was also reduced by leaf removal. Therefore, the reduction in maturity bronzing achieved by leaf removal is of no immediate benefit to growers. Removal of the male bud increased bunch weight due to an increase in finger length. Dry weight analysis indicated that the male bud represented a significant competing photosynthetic sink. For maximum yield of quality fruit, growers should remove the male bud, practice no bunch trimming, and ensure the retention of at least 9-10 leaves from flowering to harvest.