为筛选出适合在盐渍土壤中生长的高粱[Sorghum bicolor (Linn.) Moench]种质,对10 g·L^-1 NaCl 胁迫条件下65 个高粱种质萌芽期的6 项耐盐指标进行比较,并通过相关性分析和主成分分析比较了各指标在耐盐性评价中的作用;在此基础上,通过综合得分排序和聚类分析对供试65 个种质的耐盐性进行排序及评价。结果显示:供试65 个种质的相对发芽势、相对发芽率、相对根长、相对苗高和相对根冠比变幅较大,分别为0. 00% ~ 140. 56%、31. 61% ~124. 81%、10. 45% ~154. 30%、12. 80% ~124. 95%和22. 09% ~380. 84%;而相对盐害率变幅较小,仅为-8. 27% ~22. 80%。在6 个耐盐指标间,相对苗高与相对发芽率和相对盐害率的相关性以及相对根冠比与相对发芽势、相对发芽率和相对盐害率的相关性均不显著,其余指标间均有显著或极显著相关性。主成分分析中,前2 个主成分的累计贡献率为75. 121 3%,其中,相对发芽势、相对发芽率和相对盐害率为第1 主成分的主要因子,相对苗高为第2 主成分的主要因子。供试65 个种质耐盐性的综合得分为7. 18 ~65. 11;其中,甜选35 耐盐性的综合得分最高(65. 11),耐盐性排序第一;黑穗芦稷耐盐性的综合得分最低(7. 18),耐盐性排序最末。聚类分析结果显示:在欧氏距离5. 5 处,供试65 个种质可被分为7 类,其中,第玉、第域和第芋类共包含12 个种质,其中9 个为耐盐性排序前9 位的种质,属于高耐盐种质;第郁、第吁和第遇类共包含31 个种质,属于中等耐盐种质;第喻类包含22 个种质,其中10 个为耐盐性排序后10 位的种质,属于高盐敏感种质。综合分析结果表明:供试65 个高粱种质的耐盐性差异很大,其中,甜选35、Rio、宁甜选10、宁甜选11、甜选107、宁甜选17、甜选148、辽甜8 号及盐甜选10 等为高耐盐种质,适合在盐渍土壤中生长。此外,耐盐性综合得分排序结果与聚类分析结果基本一致,表明用萌芽期的耐盐指标可以初步评价高粱种质的耐盐性。

In order to select germplasms of Sorghum bicolor (Linn.) Moench suitable for growing in saline soil, six salt tolerance indexes at germination stage of 65 germplasms of S. bicolor under condition of 10g·L^-1 NaCl stress were compared, and the role of different indexes in salt tolerance evaluation was compared by correlation analysis and principal component analysis. On this basis, salt tolerance of 65 germplasms tested was ordered and evaluated by comprehensive score ordering and cluster analysis. The results show that change ranges of relative germination potential, relative germination rate, relative root length, relative seedling height and relative root-shoot ratio of 65 germplasms tested are large with 0. 00% -140. 56%, 31. 61% -124. 81%, 10. 45% -154. 30%, 12. 80% -124. 95% and 22. 09% -380. 84%, respectively. While change range of relative salt-injury rate is small only with -8. 27% -22. 80%. Among six salt tolerance indexes, correlations of relative seedling height with relative germination rate and relative salt-injury rate and those of relative root-shoot ratio with relative germination potential, relative germination rate and relative salt-injury rate are not significant, while correlations among other indexes are significant or extremely significant. In principal component analysis, cumulative contribution rate of the first two principal components is 75. 121 3%, in which, relative germination potential, relative germination rate and relative salt-injury rate are main factors of the first principal component, relative seedling height is main factor of the second principal component. The comprehensive score of salt tolerance of 65 germplasms tested is 7. 18-65. 11. In which, comprehensive score of salt tolerance of Tianxuan 35 is the highest (65. 11) and its salt tolerance order is the first, while that of Heisuiluji is the lowest (7. 18) and its salt tolerance order is the end. The cluster analysis result shows that at Euclidean distance of 5. 5, 65 germplasms tested can be divided into seven categories, in which, the Ⅰ, Ⅱand Ⅲcategories contain 12 germplasms totally, 9 of them are germplasms with salt tolerance order of top 9, belonging to high salt tolerance ermplasm; the Ⅳ,Ⅴand Ⅵcategories contain 31 germplasms totally, belonging to moderate salt tolerance germplasm; and theⅦcategory contains 22 germplasms, 10 of them are germplasms with salt tolerance order of post 10, belonging to high salt sensitive germplasm. The comprehensive analysis result shows that differences in salt tolerance of 65germplasms tested of S. bicolor are great, in which, Tianxuan 35, Rio, Ningtianxuan 10, Ningtianxuan 11, Tianxuan 107, Ningtianxuan 17, Tianxuan 148, Liaotian No. 8 and Yantianxuan 10, etc are high salt tolerance germplasms, which are suitable for growing in saline soil. Otherwise, order result of comprehensive score of salt tolerance is basically consistent with cluster analysis result, indicating that salt tolerance of S. bicolor germplasms can be preliminarily evaluated by ways of salt tolerance indexes at germination stage.