Pollination efficiency of artificial and bee pollination practices in kiwifruit

Abstract

The area cultivated with pollinator-dependent crops is increasing worldwide, while a shortfall in pollinator availability is a growing problem in many agroecosystems. For this reason, many highly pollinator-dependent crops are nowadays pollinated artificially by humans. Here, we compared the efficiency of artificial and bee pollination practices on the mean level and stability of pollination and fruit production of kiwifruit. In a kiwifruit orchard, we tagged a total of 800 flowers from 40 plants, half were pollinated by honeybees while the other half by spraying pollen on flowers, the most commonly pollination technique used in kiwifruit. During harvest, we measured fruit set, number of seeds per fruit, and fruit weight. On average, bee-pollinated plants produced 40% more fruits than artificially-pollinated plants. Also, fruits from bee-pollinated flowers contained, on average, 34% more seeds, showing also 2.8 times less variability in number of seeds per fruit than those pollinated artificially. Following the same trend, bee-pollinated flowers produce fruits that were 34% heavier and 1.5 times less variable in weight. These results showed that bee pollination resulted in higher fruit production, and heavier and more homogeneous fruits than artificial pollination. According to these results, we encourage growers and land managers to use pollination management practices based on honey bees, instead of the use of mechanical pollination systems.