The effects of bumblebees (Bombus terrestris L.) on fruit quality and yield of pepper (Capsicum annuum L.) grown in an unheated greenhouse

Abstract

Bumblebees (Bombus terrestris L.) are commonly used as a pollinator in tomato, but for pepper, other bee colonies such as Osmia cornifrons (Radoszkowski), Megachile rotundata F., and Apis mellifera L. are used for the same purpose. Here we report on the possibility of using B. terrestris as a pollinator of long-type pepper (Capsicum annuum L.) cultivars. The effects of bee pollination were compared with natural self-pollination in terms of fruit quality and yield of plants grown in a long cycle from October to May in an unheated greenhouse. Number of pollen grains/flower and pollen viability were recorded at 15-day intervals during the experimental period. The results showed that the number of pollen grains/flower decreased from January to March, and pollen germination decreased to its lowest level in January. Despite the decrease in the number of pollen grains/flower and the pollen germination percentage, bumblebee pollination was found to have a positive effect on the fruit yield, fruit quality, and seed set. The bee-pollinated plants set more seeds/fruit, and the fruit was of better quality and heavier. These results indicate that B. terrestris can be considered an effective pollinator of long-type pepper cultivars under unheated greenhouse conditions.