陆地棉苗期的耐盐碱性评价及鉴定指标筛选

为综合评价陆地棉的耐盐碱性并筛选出关键鉴定指标，以90份不同来源的陆地棉品种为试验材料，通过主成分分析、聚类分析和逐步回归法对不同品种萌发期、出苗期和苗期的耐盐碱性进行综合评价，并筛选鉴定指标。结果表明，苗期受到胁迫，棉花下胚轴、株高、叶片数及第1片真叶面积降低，出苗率和叶片SPAD值升高。相关分析表明，株高与出苗率显著正相关，与下胚轴长、叶片数和第1片真叶面积呈极显著正相关。对90份品种的综合评价D值排序，军棉1号的D值最高，耐盐碱性最强；中棉所49的D值最小，耐盐碱性最弱。根据D值进行聚类，将90份品种划分为4类：强耐盐碱品种3份、中耐盐碱品种18份、弱耐盐碱品种52份和盐敏感品种17份。依据最佳回归方程筛选出4个关键鉴定指标：出苗率、叶片SPAD值、第1片真叶面积和株高，为棉花进行初步的耐盐碱性鉴定提供了理论依据。

Evaluation and Screening of Salt and Alkali Tolerance Indices of Upland Cotton Seedlings

In order to comprehensively evaluate the salt-alkali tolerance of upland cotton and screen out the key identification indexes， 90 cotton varieties from different origins were as materials. The salt tolerances of 90 varieties were evaluated by principal component analysis， cluster analysis and stepwise regression， and the key identification indicators were screened. The results showed that the hypocotyl lengths， plant height， number of leaves， leaf area of the first true leaf of cotton at seedling stage decreased under stress， while the emergence rate and SPAD value increased. Plant height significantly positively correlated with seedling emergence rate， and extremely significantly positively correlated with hypocotyl length， leaf number and first true leaf area. According to the D values， Junmian 1 was the highest with the strongest saline-alkaline tolerance， while Zhongmiansuo 49 was the lowest with the worst saline-alkaline tolerance. And 90 varieties were classified into 4 groups including 3 varieties with strong saline-alkali resistant， 18 varieties with medium saline-alkali resistant， 52 varieties with weak saline-alkali resistant and 17 varieties with salt sensitive. According to the optimal regression equation， emergence rate， SPAD value， leaf area of the first true leaf and plant height were selected for identifying salt tolerance of cotton， which should provide theoretical basis for the preliminary identification of salt and alkali resistance of cotton.