Introduction of new tools to improve pollination in European pear orchards

Abstract

Pollination remains crucial to achieve valuable fruit yield in European pear (Pyrus communis) orchards. An innovative approach to improve pollen transfer involves the use of pollen dispensers at the hive entrance. Due to its commercial availability, Nashi (Pyrus pyrifolia) pollen is proposed in pollen dispensers fitted in bumblebee hives for European pear tree pollination. Our objectives were (1) to investigate whether Nashi pollen is suitable for pollination of European pear and (2) to assess the efficiency of pollen dispenser in bumblebee hives. To test the compatibility between both species, Nashi pollen were used in hand-pollination of two European pear tree cultivars ‘Conférence’ and ‘Doyenné du Comice’. The impact of Nashi pollen on the bumblebee behaviour was investigated at the hive exit. Nashi pollen was suitable for pollination of ‘Conférence’ and ‘Doyenné du Comice’. ‘Conférence’ fruits resulting from pollination with Nashi were smaller (53±1.5mm) than those pollinated with ‘Doyenné du Comice’ (60±1.1mm) while fruit diameter of ‘Doyenné du Comice’ did not vary with the pollen origin (71±1.3 vs. 69±1.2mm). Pollen deposit at the hive entrance did not modify bumblebee behaviour. All insects leaving the hive were covered with pollen even if their pollen charge decreased by 53% 24h after pollen deposit. All together our results suggest that Nashi pollen could be used in pollen dispenser for pollination of the European pear cultivars ‘Conférence’ and ‘Doyenné du Comice’ if pollen dispenser is refilled at least once a day.