A COMPREHENSIVE CALIFORNIA FIELD STUDY OF THE INFLUENCE OF PREHARVEST APPLICATIONS OF GIBBERELLIC ACID ON THE RIND QUALITY OF VALENCIA ORANGES

Abstract

Gibberellic acid (GA3) applications to Valencia orange (Citrus sinensis [L.] Osbeck) trees in California, performed in August or September when the target crops of young fruit were present, reduced the severity of rind crease upon maturation of the fruit. The same treatments delayed aging and softening of the rind, as demonstrated by puncture resistance measurements. In some cases, a greener rind color was associated with GA3 treatments. There were no undesirable influences an juice quality and fruit production. As regards the delay in rind softening, GA3 treatments were more efficient when applied in August than in September. Otherwise, there were no clear differences in the responses to August and September applications of GA3. The study led to the registration of GA3 for preharvest use on Valencia orange trees in California.