关键词: 芝麻, 盛花期, 高温处理, 主成分分析, 综合评价

Abstract:

【Objective】To understand the effects of high temperature stress on the agronomic traits, yield, its components and grain quality of sesame, to accurately evaluate the high temperature tolerance level of different sesame varieties at full flowering stage, and to screen the high temperature tolerant sesame varieties.【Method】24 sesame varieties were treated with normal temperature (CK) and high temperature stress(H) at full flowering stage for 7 days. The agronomic traits such as plant height, initial capsule site, number of capsules per plant, number of capsules per capsule, 1000-grain weight, yield per plant and quality indexes such as water content, oil content and protein content were measured at maturity stage. The heat tolerance of different sesame varieties at full flowering stage was comprehensively analyzed and evaluated by means of principal component and cluster analysis.【Result】Different varieties, temperature treatments and interactions had significant effects on the indexes of sesame. After high temperature stress, compared with CK, the yield per plant, 1000-grain weight, number of capsules per plant, number of capsules per capsule, initial capsule site, capsule length and plant height of sesame decreased by 33.47%, 13.62%, 7.76%, 5.75%, 2.61%, 1.64% and 1.40%, respectively. Among which 1000-grain weight and yield per plant decreased the most, and the differences reached significant level. The difference of end length and protein content was no significant, which was 13.43% and 1.55% lower than that of the CK. The water content and oil content increased by 0.90% and 0.17% respectively compared with CK, and the difference was not significant. There is a certain correlation between the high temperature tolerance coefficients of different varieties and various indexes. The high temperature resistance coefficient was analyzed by principal component analysis, and five independent comprehensive indexes were established, and the contribution rates were 30.74%, 25.82%, 13.18%, 10.12% and 8.33%, respectively, reflecting 88.19% of the original information. The weight of each index was calculated by component matrix and eigenvalue, and the physiological comprehensive index model of high temperature stress (HTSPCI) was constructed. According to the cluster heat map analysis of high temperature tolerance coefficient of each individual index, 24 sesame germplasm resources were divided into 4 grades: high temperature resistant type, medium high temperature tolerance type, medium heat sensitive type and heat sensitive type, respectively. And the yield loss rate per plant (X6) of 6 high temperature resistant varieties was ≤9.50%, 6 medium high temperature resistant varieties was 9.50%<X6≤30%, 10 medium heat sensitive varieties was 30%<X6≤70% and 2 heat sensitive varieties was X6>70%.【Conclusion】High temperature treatment significantly affected the growth and development of sesame at full flowering stage. A comprehensive index model of high temperature stress was established by combining agronomic traits and quality indexes with principal components-cluster analysis, and 6 varieties with high temperature tolerance were selected, which could be used to evaluate the high temperature tolerance of different sesame varieties.

Key words: sesame, full flowering stage, high temperature, principal component analysis, comprehensive valuation