CROP LOAD EFFECTS ON FLORAL QUALITY IN OLIVE

Alternate bearing in olive is largely determined by flowering load. In order to know if there are differences in floral quality related to f lower load, and if these differences reinforce or alleviate the altern ate-bearing tendency, we compared pistil abortion, floral sink strengt h and fruit set between ''on'' and ''off'' 'Manzanillo' olive trees. ' Manzanillo' trees with light flowering showed a higher percentage of p istillate inflorescences, higher dry weight and nitrogen content of th e flower, and a higher percentage of fruit set. The tree with the ligh test flower load had greater ovule longevity than the tree with the he aviest flower load, although differences were not found in the inciden ce of undeveloped embryo sacs. The results suggest partial compensatio n of the alternate habit by enhancement of female floral quality and a n increase in fruit set when low levels of flowering occur.