Effect of girdling mango trees in May prior to flowering in August on flowering, fruit size, yield and fruit physico-chemical characteristics at harvest and ripening

摘要

Three-year-old mango trees in commercial orchards of cultivars 'Tommy Atkins', 'Kent', 'Heidi' and 'Zill' were trunk-girdled in May prior to flowering in August. A 5-mm-wide, complete trunk girdle was made in mid-May. Non-girdled trees served as controls in five experiments, one per orchard. In the girdled trees, bud development on various trees was advanced. Abnormal shoots developed from these buds. They were rosette-like and chlorotic, and possessed leaves that were abnormally small. Growth reverted to inflorescence development in many instances. From buds breaking later, inflorescences developed. In the girdled trees, they were shorter and more compact than normal. In time, the girdled tree canopies became chlorotic, and, in a number of instances, tree death occurred. Fruit weight and yield were always reduced, and fruit ground skin colouration always enhanced in the girdled trees. Visually, the fruits on the girdled trees were smaller and lighter green at harvest. Number of fruits retained wasincreased in 'Tommy Atkins'. A difference in this regard was not clear in the remaining cultivars. Inflorescence number was reduced in 'Kent', whereas it was increased in 'Heidi' and 'Zill'. Inflorescence development was delayed in 'Tommy Atkins' and 'Kent'. A difference in this regard was not evident in 'Zill'. Harvest pulp colouration was less intense and total soluble solids (TSS) content was increased in 'Heidi'. Harvest pulp coloration and TSS content were increased in 'Zill'. A change in shelf-life resulting from girdling was not apparent in any of the cultivars. Ripe skin coloration was reduced in 'Tommy Atkins', and increased in 'Kent' and 'Heidi'. TSS content on ripening was increased in 'Kent', 'Heidi' and 'Zill', but reduced in 'Tommy Atkins'. The general effect of girdling was a reduction in fruit size, a reduction in tree yield, and an increase in harvest skin coloration and TSS content in ripening. Inconsistent results appeared to pertain to the effect of girdling on bud-break; girdlingstimulating early bud-break or delaying bud-break. In view of these results, girdling of mango trees at the time of year and manner carried out in the present study is not recommended.