Bees increase crop yield in an alleged pollinator-independent almond variety

Agustin Sáez,Marcelo A Aizen,Ethel Villalobos,Matias Viel,Sandra Medici,Pedro Negri

doi:10.1038/s41598-020-59995-0

Abstract

Wild pollinators are declining and the number of managed honey bee colonies is growing slower than agricultural demands for pollination. Because of these contrasting trends in pollinator demand and availability, breeding programs for many pollinator-dependent crops have focused on reducing the need for pollinators. Although numerous crop varieties are now available in the market with the label of pollinator-independent, the real dependence of these varieties on pollinators is mostly unknown. We evaluated the hypothesis of pollinator independence in the Independence almond variety, the fastest growing variety in California that is the main almond production region in the world. In this presumed pollinator-independent variety, we measured the effect of honey bees on fruit set, yield, and kernel nutritional quality at tree level. Fruit set was 60% higher in bee-pollinated than bee-isolated trees, which translated into a 20% increase in kernel yield. Despite its effect on almond production, there was no evidence that bee visitation affected almond nutritional quality. Based on these results, we recommend the use of bees, whether they are wild or managed, to maximize yield even in self-fertile almond varieties.

Highlights

Wild pollinators are declining and the number of managed honey bee colonies is growing slower than agricultural demands for pollination
We measured the effect of bees on fruit set, kernel yield, and kernel nutritional quality on the “self-fertile” Independence almond variety
Managed honey bees accounted for all flower visits to the self-compatible Independence almond variety

Summary

Introduction

Wild pollinators are declining and the number of managed honey bee colonies is growing slower than agricultural demands for pollination. Wild pollinators are declining whereas managed honey bees are growing slower than agricultural demands for pollination[4,5] Because of these uneven trends in pollinator demand and availability, breeding programs for many pollinator-dependent crops are targeted to reducing the need of biotic transfer of pollen for ovule fertilization, and for seed and fruit production. This was meant to be a massive breakthrough for almond industry, because this new variety was advertised as bee-independent due to self-fertility and its presumed high capacity for autonomous self-pollination[7,17,18] Cultivation of this variety would, in principle, benefit growers by removing the costs of renting bee colonies, among other advantages. If this variety were fully self-fertile and capable of autonomous self-pollination, we should observe a similar fruit set, and kernel yield and quality in trees visited as in those not visited by bees

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Conclusion