模拟干旱条件下玉米品种萌发期抗旱性评价

采用20%PEG-6000模拟中度干旱胁迫对41份玉米品种的萌发期进行抗旱性试验,通过加权隶属函数法计算综合评价值(D值)对供试材料的抗旱性进行综合评价,利用UPGMA聚类划分抗旱等级。结果表明,发芽率、发芽势、胚芽鞘长、主胚根长、胚根数和干物质重6个性状,干旱胁迫处理比对照均值分别下降了50.8%、65.6%、81.4%、57.9%、42.1%和70.0%,不同品种间差异显著。隶属函数法计算D值表明,其与发芽率、胚芽鞘长等各指标抗旱系数的隶属函数值均呈极显著正相关,筛选出金海5号、粟玉6号等13个抗旱品种。UPGMA聚类分析将试验材料在遗传距离为6.91处分为2大类,进一步可分为高度抗旱、中度抗旱、抗旱、敏感、高度敏感共5个亚群,玉米萌发期较强抗旱品种为粟玉6号、京农科728等13个品种。两种方法筛选出的玉米萌发期抗旱品种高度吻合。

Evaluation of Drought Resistance of Different Maize Varieties under Drought Stress Simulation at Germination Stage

The drought resistance of 41 maize germplasms was evaluated by 20% PEG-6000 simulating moderate drought stress to sceen drought-resistant maize varieties. Then the weighting membership function and D value were used to evaluate the drought resistance, and the drought resistance grade was divided by UPGMA cluster. The germination rate, germination potential, coleoptile length, main radicle length, radicle number and dry matter weight of the tested materials were measured in this experiment. The results showed that the mean values of the treatment group were 50.8%, 65.6%, 81.4%, 57.9%, 42.1% and 70.0% lower than those of the control group, respectively and the differences between different varieties were significant. However, we found that the 20% PEG-6000 simulation stress promoted the main radicle growth of some varieties, which suggests that these materials may be strong drought resistant varieties at the germination stage. Moreover, D value calculated by the weighting membership function method showed that it had a significantly positive correlation with drought resistance indices, such as germination rate and coleoptile length. Based on the result, 13 drought-resistance germplasms such as Jinhai 5, Suyu 6, Jingnongke728, etc. were screened out. Through UPGMA clustering analysis, the materials were divided into two major categories at the genetic distance of 6.91. Furthermore, it could be divided into 5 subgroups:high drought resistance, moderate drought resistance, drought resistance, sensitivity and high sensitivity. Therein, the screened maize varieties with strong drought resistance at germination stage were Suyu 6, Jingnongke728, Jinhai 5, etc. Noticeably, the two methods screening drought-resistent maize varieties at germination stage were highly consistent.