Hormonal relations in fruits growth and development of Coffea arabica L

Growth of coffee fruits follows the pattern of a typical double-sigmoid curve. Following anthesis, young fruits called `pinheads' remain quiescent for about 6-8 weeks. This is apparently due to the lack of most of the growth substances. This has been shown by studying changes in endogenous growth regulators at various stages of development. Gibberellic acid applied onto 4-6 weeks old fruits has been shown to increase both the growth rates of the fruits and dry weight of the beans and also to improve bean quality. Application of cytokinin did not, however, give any better effect. Under Kenyan conditions there are normally crops of different ages present on the trees at any one time. Attempts to regulate cropping using GA subíndice 3 and other growth regulators have met with limited success. CEPA, an ethylene releasing compound, was shown to promote ripening. Applied at the correct stage of fruit development, CEPA can be used as a tool in obtaining flexibility in harvesting. The practical implications of this work are discussed