Comprehensive Evaluation and Screening of High Temperature Resistance and Yield of Oil Peony ‘Fengdan’

Fifty-nine oil peony ‘Fengdan’ individual plants were used as experimental materials.Correlation analysis, factor analysis and cluster analysis were used to study the effects of summer high temperature on the agronomic characters and resistance indexes of ‘Fengdan’,in order to provide reference for the high temperature resistance breeding of oil peony.The results showed that the characters of each plant were significantly different, and the average coefficient of variation was 33.61%.Correlation analysis showed that the yield-related traits such as crown width, number of fruits, number of seeds in a plant, yield per plant were significantly positively correlated, while the high temperature resistant traits such as high temperature damage index, SPAD value, water content and electrical conductivity were significantly correlated.Factor analysis showed that 6 main factors were extracted from 19 indices, with a cumulative contribution rate of 74.876%.The first factor was yield factor, with variance contribution approached to 28.351%.The second factor was seed factor, with variance contribution approached to 13.756%.The third factor was high temperature resistance factor, with variance contribution approached to 11.040%.The latter three factors had low contribution rates and were collectively referred to as other factors.Cluster analysis showed that 59 individual plants could be divided into four grades at 5.0 square Euclidean distance, and 5 excellent individual plants with high temperature resistance and high yield were screened out.