Citrus fruit quality

Physiological basis and techniques of improvement.

Abstract

Fruit size can be improved either by increasing carbohydrates availability to fruit or by increasing fruit sink strength. Application of synthetic auxins may act in these two ways, depending on the date of treatment. When they are applied during the physiological drop  they have a thinning effect, reducing competition for carbohydrates among developing fruitlets; when applied at the onset of cell enlargement stage fruit sink strength is increased and carbohydrate accumulation in the fruit is enhanced. 

Physiological disorders such as creasing, splitting, piffing, peel pitting, etc. Can be reduced in intensity or minimized using gibberellic acid, synthetic auxins or a mixture of both. Fruit maturation (colouring) can be  enhanced using ethephon or figaron and can be delayed using gibberellic acid. The effectiveness of some of these treatments can be significantly improved by adding mineral salts, mainly nitrogen compounds in the spray mix. In this article best treatment strategies and their mechanism of action are discussed.