Crop Cycle Influences the Effectiveness of Pollination Techniques in Greenhouse Tomato

摘要

Fruit set limits the productivity of the tomato crop in the greenhouse. In North Mediterranean conditions two tomato crop cycles can be carried out in the same year. Environmental constraints limiting pollination in the cycles may impose the use of different pollination techniques, both from the productive and from the economical point of view. The aim of this study is to analyze whether flower vibration, bumblebee pollination, or auxin spraying, improve fruit production of early and late tomato greenhouse crops.Treatments were more effective in the early crop, carried out in spring, than in the late one in summer-autumn. For both crop cycles, the highest production was for the bumblebee pollinated plants. The mechanical flower vibration technique and the auxin treatment significantly increased production in the early crop, but they were ineffective in the late cycle crop. However, treating the early crop with auxins may result in nipple-shape fruits. Earliness was not affected by the treatments. Fruit set was improved by all treatments tested and in both crop cycles. In both seasons, the use of bumblebees was the most successful treatment, and the maximum effectiveness was observed during the periods of low night temperatures in the early cycle, when fruit set was limited due to impaired production of viable pollen and/or poor pollen release. Auxin and vibration enhancement of fruit set was higher for the early than for the late crop cycle. The environmental conditions were determinant for the effectiveness of the treatments. Moreover, the bumblebee efficiency was demonstrated not only when the climatic factors were limiting for tomato fruit set, but also when fruit-set was not limited by natural climatic conditions.