自然条件与冷水胁迫下水稻主要农艺性状的表型差异OA

In order to explore the effects of cold water stress on major agronomic traits of rice and the differences in cold tolerance among rice varieties from different geographical origins,this study used 306 accessions of japonica rice varieties originating from six Chinese provinces(autonomous regions and municipalities)and five foreign countries as test materials.Filed trials under two treatments natural growth conditions and cold water stress were established at the Gongzhuling Expermental Base in Jilin province in 2017 and 2018,with precision phenotypic identification conducted for traits including days to heading,plant height,effective panicles per plant,grains per panicle and seed setting rate.The results showed that cold water stress markedly suppressed rice growth and development compared to natural conditions,resulting in postponed heading,shortened plant height,and highly significant declines in effective panicles per plant,grains per panicle,and seed setting rate.Notably,the seed setting rate decreased by 52％,suffering the most substantial adverse impact.Based on assessments of the cold response index(CRI)and stability coefficient for major agronomic traits,rice varieties originating from Yunnan of China,Japan,and Korea showed higher CRI in yield-related traits,signifying enhanced cold tolerance.Meanwhile rice accessions from Italy,Korea,Japan,Liaoning and Jilin of China displayed smaller stability coefficients,suggesting better environmental adaptability.Cluster analysis showed that the genetic relatedness among most tested varieties was partially associated with the geographical distance and latitude similarity of their prvenances.Meanwhile,20 cold tolerant elite germplasms,such as Huajindao,Qiandaijin,Liaojing287,Ningjing 36,and 06-2391,were screened out in this study,offering valuable material resources for rice cold tolerance breeding.