青海高原53份人工合成小麦种子萌发期的耐盐性评价

Evaluation of salt tolerance in seed germination stage of 53 synthetic hexaploid wheat accessions in the Qinghai Plateau

关键词:  青海高原, 人工合成小麦, 萌发期耐盐性, 耐盐种质鉴定, 灰色关联分析

Key words:  Qinghai Plateau, synthetic hexaploid wheat, germination-stage salt tolerance, salt-tolerant germplasm identification, grey relational analysis

摘要:

为揭示青海高原中度盐渍土盐胁迫条件下人工合成小麦种子萌发期耐盐性差异,并鉴选出适宜当地种植的耐盐种质,该研究以43份人工合成小麦为材料,在0 mol·L^-1 NaCl(对照)和0.08 mol·L^-1 NaCl盐胁迫条件下,测定其发芽率、苗长等关键萌发期各性状指标,并运用灰色关联分析结合聚类分析对供试材料进行耐盐性评价。结果表明:(1)供试人工合成小麦各性状的耐盐指数变异系数范围为28.41%～59.41%,地下部鲜重的耐盐指数较高,为1.05; 盐胁迫处理下,供试人工合成小麦的苗长、胚芽鞘长、最大根长和地上部鲜重均明显高于‘高原448',同时苗长、胚芽鞘长和地下部鲜重的耐盐指数均高于‘高原448'。(2)供试人工合成小麦的苗长权重最高,为18.89%,综合评价排名前十的材料依次为27号、9号、15号、31号、28号、29号、30号、37号、12号和25号。(3)聚类分析结果显示,44份供试材料可分为5类,其中类群Ⅰ为较耐盐类群,类群Ⅱ为极耐盐类群,以栽培二粒小麦为母本创制的全部9份人工合成小麦材料主要分布在类群Ⅰ和类群Ⅱ中; 综合评价前十的材料类群Ⅱ包含7份,分别为9号、27号、15号、31号、28号、29号和30号。该研究综合评价了人工合成小麦在盐胁迫条件下种子萌发期主要农艺性状的变化,筛选出适宜青海等中度盐渍化地区种植的人工合成小麦优异种质资源,并进一步提出了以栽培二粒小麦为母本创制更多人工合成小麦用于耐盐新种质的鉴定和评价,这为选育适宜青海等地区中、轻度盐渍化土地种植的耐盐小麦新品种提供种质基础,为解析小麦耐盐分子机制提供理论依据。

Abstract:

To reveal the differences in salt tolerance of synthetic hexaploid wheat during seed germination stage under moderate saline soil salt stress on the Qinghai Plateau, and to identify salt-tolerant germplasm suitable for local cultivation, this study used 43 synthetic hexaploid wheat accessions, under the conditions of 0 mol·L^-1 NaCl(control)and 0.08 mol·L^-1 NaCl salt stress, key germination stage traits(such as germination rate and seedling length)were measured. Grey correlation analysis combined with cluster analysis was applied to evaluate the salt tolerance of the tested materials. The results were as follows:(1)The coefficient of variation for the salt tolerance index of each trait in the tested synthetic hexaploid wheat ranged from 28.41% to 59.41%, with the salt tolerance index of underground fresh weight being the highest at 1.05. Under salt stress treatment, the seedling length, coleoptile length, maximum root length, and shoot fresh weight of the tested synthetic hexaploid wheat were all significantly higher than those of ‘Gaoyuan 448'; meanwhile, the salt tolerance indices of seedling length, coleoptile length, and root fresh weight were also higher than those of ‘Gaoyuan 448'.(2)Among the tested synthetic hexaploid wheat accessions, seedling length had the highest weight(18.89%). The top 10 materials ranked by comprehensive evaluation were No. 27, No. 9, No. 15, No. 31, No. 28, No. 29, No. 30, No. 37, No. 12, and No. 25 in sequence.(3)The result of cluster analysis showed that the 44 tested materials could be classified into 5 clusters. Among them, Cluster Ⅰ was the moderately salt-tolerant group, and Cluster Ⅱ was the highly salt-tolerant group. All 9 synthetic hexaploid wheat materials developed with Triticum dicoccum(cultivated emmer wheat)as the female parent were mainly distributed in Cluster Ⅰ and Cluster Ⅱ. Additionally, Cluster Ⅱ contained 7 of the top 10 materials in the comprehensive evaluation, namely No. 9, No. 27, No. 15, No. 31, No. 28, No. 29, and No. 30. This study comprehensively evaluates the changes in key agronomic traits of synthetic hexaploid wheat during seed germination under salt stress. It screens out excellent synthetic hexaploid wheat germplasm resources suitable for cultivation in moderately salinized areas such as Qinghai, and further proposes that Triticum dicoccum can be used as the female parent to create more synthetic hexaploid wheat, which can be applied to the identification and evaluation of new salt-tolerant germplasm. This research provides a germplasm foundation for breeding new salt-tolerant wheat varieties suitable for slightly to moderately salinized lands in regions like Qinghai, and offers a theoretical basis for dissecting the molecular mechanisms of salt tolerance in wheat.