Abstract

Biennial or alternate bearing is one of the greatest production and economic problems of olive growing, for both table and oil olives, as crop load is a determining factor in the persistence of this phenomenon. The aim of this study was to examine the influence of crop load on the degree of alternate bearing of Frantoio olive trees and its effect on some production variables. To do this, a follow-up was made of oil accumulation in the final period of fruit growth during the 2011-2012 and 2012-2013 seasons, with low and high crop loads, respectively. At harvest, the following fruit aspects were evaluated: concentration and content of pulp oil, pulp/pit ratio, fruit and mesocarp weight. At the same time, per tree production was determined to estimate crop load and oil yield. The main results show crop load heavily influences the variables assessed. It was observed that the average production of a tree over two consecutive seasons with low and high crop loads remains constant, regardless of the production level of the trees, suggesting an optimal yield potential where alternate bearing plays no part. This potential, in turn, seems to be related to the rate of maximum gain of oil yield per kg of fruit produced. Thus, when the production optimum is exceeded in a year with a high crop load, this rate falls.