Abstract:

In this study, 10 foxtail millet (Setaria italica L.) germplasm accessions were treated with varying concentrations of NaCl solution. By analyzing four indexes, including the relative germination potential, relative germination rate, relative shoot length, and relative root length during germination stage, we established that the suitable NaCl concentration for the identification of salt tolerance during germination in foxtail millet was 180 mmol/L. To evaluate the salt-tolerance of 180 core germplasms during the germination stage, correlation analysis and principal component analysis were employed to calculate the aforementioned four traits under 180 mmol/L NaCl treatment. Comprehensive evaluation and salt-tolerant grade of the 180 germplasms were identified by membership functional analysis and cluster analysis. Results revealed that except for the non-significant correlation between relative germination rate and relative shoot length, all other indexes showed a highly significant positive correlation. Furthermore, principal component analysis suggested that the four indexes could be considered as key indices for assessing salt tolerance. Cluster analysis revealed that the 180 germplasms could be divided into four groups: highly salt tolerant, salt tolerant, salt sensitive, and extremely salt sensitive. Jiangu, Henggu 12, Qitoubai, K-3606, and Jingu 20 were identified as extremely salt tolerant accessions through comprehensive evaluation using membership function. In addition, under 180 mmol/L NaCl stress, 40 lines from the F7 generation recombinant inbred line (RIL) of Heizhigu (extremely salt-sensitive)×Changnong 35 (salt-tolerant) were analyzed. Results showed significant variation among the 40 lines, with their frequency distribution of salt tolerance grades approximating normal distribution, indicating that this population was suitable for salt-tolerant QTL mapping. These findings demonstrated that 180 mmol/L NaCl could be used for the identification of salt-tolerant foxtail millet germplasms during the germination stage and that at this concentration, salt tolerance differences among various germplasms can be better distinguished by four indexes: relative germination potential, relative germination rate, relative shoot length, and relative root length.

摘要：

本研究利用不同浓度NaCl溶液对10份谷子（Setaria italica L.）种质进行处理，通过分析其萌发期的相对发芽势、相对发芽率、相对芽长以及相对根长等4项指标，明确了适于谷子萌发期耐盐性鉴定的NaCl浓度为180 mmol/L。在该浓度下，利用主成分分析和聚类分析等方法，对180份种质资源进行了耐盐性综合评价和等级划分。结果显示，除相对发芽率和相对芽长之间相关性不显著以外，其余指标之间均呈极显著正相关；主成分分析结果表明，这4项指标可作为谷子耐盐性评价的重要指标；聚类分析结果将180份谷子种质分为极端耐盐、耐盐、盐敏感和极端盐敏感4类；进一步采用隶属函数进行综合评价，筛选到硷谷、衡谷12、齐头白、K-3606和晋谷20等5份极端耐盐种质材料。最后，在该浓度处理下，对黑枝谷×长农35号（极端盐敏感×耐盐）F7代重组近交系遗传群体进行了初步分析，发现40份株系耐盐性等级频率分布近似正态分布，表明该群体适宜耐盐QTL挖掘。研究结果说明，在180 mmol/L NaCl处理下，通过谷子萌发期相对发芽势、相对发芽率、相对芽长和相对根长等4个指标能较好地区分不同种质耐盐性的差异。