If the tree is permitted to mature an excessive crop, it becomes devitalised to the point where it not only produces an inferior produce but it becomes increasingly susceptible to diseases. So in order to ensure proper balance, thinning is practised in certain fruit crops. Thinning is the removal of a part of flower buds, flowers or fruits (before it natural) with the object of: (i) To increase the annual yield and marketable, fruits. (ii) To improve the fruit size and colour. (iii) It reduces the chance of large breakage. (iv) If promotes tree vigour and ensures more regular bearing. (v) It promotes more thorough spraying and dusting of fruits.
(vi) It ensures uniform ripening.
(i) Blossom thinning to prevent exhaustion. (ii) Marble stage thinning to prevent over crowding. (iii) Thinning after natural fruit drop of young fruits. The amount of thinning of fruits depends upon 1. Fruit set 2.
Response of the variety to thinning 3. Nature of pruning gives 4. Age of the tree 5. Value of increased sized fruits in market.
1. Hand thinning: Costly, advisable, hand thinning of pea sized berries is beneficial in grapes. Manual thinning is commonly practised in date palm.
2. Chemical thinning: NAA 100 ppm when applied 2 to 4 weeks after petal fall stage in grapes reduces fruit set in Anab-e-sahi variety of grapes. In mandarin, NAA, 600 ppm on marble sized stage is recommended to thin the overbearing fruits so as to increase the size and quality of fruit.