甘蔗常用亲本的田间自然耐寒性测定及评价.

[Objective]The present paper aimed to understand the cold tolerance of sugarcane main parents and the change characteristics of cold tolerance evaluation related traits, and to provide reference for breeding cold tolerance sugarcane varieties and reducing the harm of frost to sugarcane production. [Method] A total of 102 parents were selected for natural frost test in 5 crops consisted of two plant cane( 2017P and 2019P) and 3-year ratoon crops(2018F, 2019S and 2020F) during 2017-2020 in Zizhong, Sichuan, a frost prone area. The correlation analysis, variance analysis, calculation of broad sense heritability and cluster classification were processed. [Result] It was found that there were differences in the types and degree of cold damaged traits among parents under low temperature environments, and ratoon cane was more vulnerable than plant cane. The damaged traits were significantly ( P < 0. 05 ) correlated with some agronomic characters under cold or light frost. The performance of damaged traits was affected by parent, year and their interaction. The damage rate of plant was a high heritability trait, which can be used to evaluate cold tolerance under cold and light frost. The damage rate of stalk length and internode were medium heritability traits, which were less affected by low temperature environments, and can be used to evaluate cold tolerance, and the damage rate of internode was slightly better than that of stalk length. The percentage of green leaves varies greatly among years, which can be used for cold tolerance evaluation under light or moderate frost. The percentage of parental variance decreased, and the heritability also decreased when combined data from different trials were used for variance analysis. Cluster classification showed that trials plant crops in 2017 and 2019 were not suitable for the evaluation of cold tolerance of parents. Among the tested parents, 58. 89% of the parents were identified as good or better cold tolerance and 23. 53 % as poor or poorer.[Conclusion] There are differences in the types and degree of cold damaged traits among parents under low temperature environments, and the cold tolerance of sugarcane belongs to medium to high heritability. The traits that can be used for cold tolerance evaluation are affected by the degree of low temperature. Mild and severe low temperature stress should be set for indoor cold tolerance test. [ABSTRACT FROM AUTHOR]