Analysis of Chilling-Tolerance and Determination of Chilling-Tolerance Evaluation Indicators in Cotton of Different Genotypes
[Objective] The objective of this study was to investigate the chilling tolerance of cotton seedlings of different genotypes, to screen suitable evaluation indicators of chilling-tolerance, and to establish the mathematical evaluation model on cold tolerance, which would provide a theoretical basis for discovery and promotion of chilling tolerant germplasm, breeding of new chilling-tolerant varieties and evaluation on chilling tolerance of a large number of cotton varieties. [Method] The chilling comprehensive evaluation of chilling tolerant coefficient (CTC) about photosynthetic gas exchange parameters, chlorophyll fluorescence kinetics indexes, chlorophyll content, relative soluble sugar content, relative MDA content, relative proline content and relative electric conductivity in leaves of cotton seedlings of fifteen different genotypes under low temperature stress (5°C, 12 h) and recovery treatment (25"C, 24 h) were evaluated by principal components analysis, hierarchical cluster analysis and regression analysis. [Result] The results showed that the 12 single indexes could be classified into 7 independent comprehensive components. The cluster analysis was used to divide 15 cotton cultivars into three chilling-tolerance types. The mathematical evaluation model for cotton cold tolerance was established, D=0.215-0.244Fo1+0.206Fv/Fm1+0.32gs-0.056SS+0.225MDA+0.038ER(R2=0.995), andthe evaluation accuracy of the equation is higher than 94.25%. Six indexes closely related to the chilling tolerance, Fo,, Fv/Fm,, gs2, SS, MDA and REC, were screened, too. [Conclusion] Higher chilling tolerant varieties, which had lighter injury under low temperature stress, were able to maintain more photosynthetic electron transport capacity, and higher stomatal conductance after recovery treatment was contributed to gas exchange and recovery of photosynthetic. Determination of the six indicators under the same condition can be used for rapid identification and prediction of other cotton varieties, which is very useful for the breeding, promotion, identification and screening of chilling tolerant germplasm.
国家科技期刊平台
NSTL
万方数据
维普
