Thinning effects on Citrus Yield and Fruit Size
Thinning is performed in Citrus to increase fruit size and thus to enhance the market value of the crop. Fruit count is reduced and crop yield may be either unchanged or markedly reduced depending on the thinning procedure used.
The sink strength of the fruitlets, which determines fruitlet growth rate, is largely determined during the early stages of development. It may be increased reducing flower formation through the application of gibberellic acid during the winter rest period. In some cultivars this reduction in flower number results in an increase in the size of the ovaries and a faster early fruitlet growth rate. Also, the application of a synthetic auxin at flower opening increases selectively in most cultivars the sink strength of some of the ovaries. In both cases, the final number of fruits set is reduced in an indirect way and final fruit size is increased. Crop yield is not affected significantly.
