Effect of crop load on fruit size and nutrients in fruit parts of mango 'Num Dok Mai Sithong'

This study was to investigate the effects of the numbers of fruit per tree or 'crop loading' on fruit weight and nutrient content in mango 'Num Dok Mai Sithong'. The experiment was conducted on six-year-old mango trees in an orchard located in the Banhat district of Khon Kaen province during the off-season production period of June to September, 2013. The tree spacing was 6x4 m. The experimental design was a completely randomized design (CRD) with four types of fruit loading (70, 80, 90, and 100 fruits tree(-1)). Fruit loads were created by fruit thinning at 40 days after full bloom. The measurement at fruit maturity consisted of the weight of the whole fruit, peel, pulp, and seed with endocarp. The nutrient contents in each separated fruit part were analyzed for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and boron (B). The results determined that the varied number of fruits per tree had no effect on either the whole fruit weight or the separated fruit part weight; however, the highest total yield was achieved by the treatment of 100 fruits tree(-1). Nutrient contents within the fruit parts also exhibited no significant effects from fruit loading in all treatments. Nutrient levels, within the optimum fruit load of 70-100 fruits tree(-1) (360 g), for N, P, K, Ca, Mg and B in the studied fruits (360 g) were 435.08, 57.84, 656.81, 16.56, and 90.62 mg fruit(-1) and 571.29 mu g fruit(-1), respectively.