The floral biology of the olive: II. The effect of inflorescence load and distribution per shoot on fruit set and load

Abstract

The effect of inflorescence number and distribution along the shoot on the level of fruit-set was studied using `ON' year olive trees with a high level of floral differentiation. Reduced levels and different inflorescence distribution patterns were created artificially by hand inflorescence thinning. In most cases, removal of up to 50% of the inflorescences had either no effect on the total amount of fruit load per shoot or increased it significantly. Thus, the percentage of fruit set increased with the reduction in inflorescence number due to both, a higher percentage of fruitful inflorescences and higher numbers of fruits per inflorescence. Inflorescences on the distal half of cv. Barnea shoots were less fruitful than on the proximal half. With cv. Manzanillo no such difference was found. Single inflorescence distribution significantly raised the level of both, the fruit load and fruit set compared with distribution of the inflorescences along the shoot in pairs, although the amount of this increase varied with the different thinning levels. The actual percent of fruit set on a flower number basis increased in parallel with the reduction of their number in response to inflorescence thinning.