Effects of bee pollination on yield and quality of oil tree peony in the extreme weather spring freeze

Author of the article:ZHANG Kai-Kue, WANG Xiang, BAO Jun-Yi, WANG Hao, HE Chun-Ling, HOU Xiao-Gai

Author's Workplace：College of Agriculture, Tree Peony, Henan University of Science & Technology, Luoyang 471000, China

Key Words：spring freeze; oil tree peony; Apis mellifera; Bombus terrestris; pollination; yield

Abstract：[Objectives]  Spring freeze is a typical climate disaster, which will seriously affect the growth and yield of agricultural and forestry crops. Bee pollination can significantly improve the yield, quality and economic value of crops. This study took the oil tree peony ‘Fengdan’ as the research object, and aimed to determine whether bee pollination could alleviate the impact of spring freeze on crop yield and quality, and lay a foundation for the effective use of bee resources. [Methods]  From 2017 to 2020, Apis mellifera and Bombus terrestris were placed in the pollination net room of the oil tree peony base to determine the fruit, yield and quality in different years and different pollination methods in the same year. At the same time, under the influence of the spring freeze, the effect of pollination by A. mellifera and B. terrestris on the yield and quality of oil tree peonies was focused on comparative analysis. [Results]  In 2018, the freezing injury rate of stamens in the oil tree peony field reached 70.20% and the per plant yield was (4.85±0.81)g, which significantly reduced by 1 094.86%, 1 401.24% and 893.60%, respectively (P < 0.01). The results over 4 consecutive years show that A. mellifera and B. terrestris significantly increase the per plant yield of oil tree peonies by 85.43%-499.38% and 35.86%-357.94%, respectively (P < 0.01), and that A. mellifera increases the yield more than B. terrestris. In 2018, A. mellifera pollination significantly alleviated the reduction in yield per plant by 499.38% (P < 0.01), whereas pollination by B. terrestris significantly alleviated it by 203.71% (P < 0.01). There was no significant difference in the oil yield, or total unsaturated fatty acid content, of tree peonies pollinated by either A. mellifera or B. terrestris (P < 0.05). A. mellifera pollination reduced the yield reduction rate of oil tree peonies by 407.18%, whereas pollination by B. terrestris reduced the yield reduction rate by 133.04%. [Conclusion]  Spring freeze significantly reduced the yield of oil tree peonies, but did not affect their productivity the following year. Pollination by either A. mellifera or B. terrestris can significantly alleviate the adverse impact of a spring freeze on oil tree peony yields, the former more so than the latter.