西南麦区小麦品种萌发期抗旱性的综合鉴定及评价

为筛选西南麦区小麦萌发期抗旱性强的品种,用20％ PEG-6000水溶液模拟干旱胁迫,测定41个小麦品种的发芽势、发芽率、发芽指数、苗高、胚芽鞘长度、胚根长、胚根数等性状,并通过加权隶属函数法对供试材料的抗旱性进行综合评价.结果表明,与正常条件相比,20％ PEG-6000胁迫下小麦种子胚根数均降低(西科麦5号和川麦104例外),发芽势、发芽率、发芽指数、苗高、胚芽鞘长度、根长均受到抑制,且不同品种降幅不同.通过加权隶属函数法分析,综合评价值(D值)较大的前五位品种分别是蜀万8号、绵麦228、绵麦37、川麦104和内麦316.利用聚类分析对41个品种的抗旱性进行分类,蜀万8号、绵麦37等5个品种为高度抗旱品种;川麦60、昌麦30等13个品种为抗旱品种;内麦9号、川麦43等10个品种为中等抗旱品种;绵阳26、蜀麦482等8个品种为对水分胁迫敏感品种;川麦55、川麦42等5个品种为对水分胁迫高度敏感品种.除根长外,其他鉴定指标与D值呈极显著正相关,发芽率和发芽指数与D值的相关系数最大(0.87).发芽率和发芽指数可作为小麦萌发期抗旱性快速鉴定的参考指标.强抗旱性品种蜀万8号、绵麦37、绵麦228等可作为西南麦区小麦抗旱育种种质资源.

Identification and Evaluation of Wheat Cultivars for Drought Resistance during Germination in Southwest Area

Drought at germination is a main factor limiting wheat emergence. The objectives of this study were to screen strong drought resistance wheat varieties for mechanical sowing in the southwest hilly areas and provide some identification index for drought resistance breeding. A hydroponic experiment was conducted to measure the germination potential,germination rate,germination index,seeding height,coleoptile length,radicle length,radicle number of 41 wheat varieties under simulated drought stress with 20% PEG-6000,and the comprehensive evaluation for drought resistance of each variety was conducted by weighting the membership functions and cluster analysis. The results suggested that: compared with normal condition,the radicle number were decreased except for Xikemai 5,Chuanmai 104 and the germination potential,germination rate,germination index,seedling height,coleoptile length,radicle length were all decreased to different extent for the diverse varieties under 20% PEG-6000 simulation stress. Weighted membership function analysis showed that Shuwan 8,Mianmai 228,Mianmai 37,Chuanmai 104 and Neimai 316 had higher D values; clustering analysis indicated that the 41 varieties could be classified as: five with highly resistant (Level 1,e.g. Shuwan 8 and Mianmai 37,etc.),thirteen with drought resistant (Level 2,e.g. Chuanmai 60,Changmai 30,etc.),ten with moderate resistant (Level 3,e.g. Neimai 9,Chuanmai 43,etc.),eight with sensitive (Level 4,e.g. Mianyang 26,Shumai 482) and five with highly sensitive (Level 5,e.g. Chuanmai 55,Chuanmai 42,etc.). Besides,except for radicle length,the other indexes showed significant and positive correlation with the weighted membership function value (D value),among which germination rate and germination index had the highest correlation coefficients with D value(0.87),which could be served as the rapid identification index for wheat drought tolerance during germination stage in Southwest area. The three highly drought tolerant varieties (Suwan 8,Mianmai 37 and Mianmai 228) can be used to further research for drought tolerance mechanism and be served as germplasm resource for drought tolerance breeding.