30份大麦种质资源的苗期抗旱性鉴定及抗旱指标筛选

Drought Resistance Identification and Drought Resistance Indices Screening of 30 Barley Germplasm Resources at Seedling Stage

在西北内陆地区,干旱是影响大麦生长发育的重要非生物胁迫因素,鉴定大麦资源的抗旱性,确定抗旱指标,筛选抗旱种质,培育抗旱品种具有重要意义。以30份大麦种质为材料,设置正常供水和反复干旱胁迫2个处理,在旱棚内进行盆栽试验,测定干旱对株高、根长、叶长、地上部鲜重、根鲜重、地上部干重、根干重和总干重的影响;采用抗旱性度量值(D值)、综合抗旱系数(CDC值)、加权抗旱系数(WDC)、频次分析、相关分析、主成分分析、灰色关联度分析、隶属函数分析、聚类分析和逐步回归分析相结合的方法,对其进行苗期抗旱性鉴定及抗旱指标筛选。结果显示干旱胁迫对各指标均有极显著影响。频次分析表明,各指标对干旱胁迫反应的敏感程度依次为根长、根干重、总干重、地上部鲜重、地上干重、叶长、根鲜重和株高;相关分析表明,总干重与根干重、地上部干重、叶长和根长呈极显著正相关,与地上部鲜重呈显著正相关,与株高和根鲜重呈不显著正相关;主成分分析表明,4个主成分可代表大麦种质资源抗旱性83.583%的原始数据信息量。基于D值、CDC值和WDC值的供试大麦种质抗旱性排序相近。灰色关联度分析表明,各指标DC值与D值间的关联度大小依次为株高、地上部干重、总干重、叶长、地上部鲜重、根长、根干重、根鲜重,与各指标DC值与WDC值关联度大小排序基本吻合。根据D值进行聚类分析,可将供试大麦种质划分为5个抗旱级别,其中1级2份、2级13份、3级6份、4级7份、5级2份。除根鲜重、地上部干重、根干重和总干重外,其余指标的隶属函数值、CDC值、D值和WDC值均随抗旱级别的升高而增大。逐步回归分析表明,与D值密切相关的指标有株高和总干重。苗期抗旱性强的大麦种质资源材料有西藏25和NEVADA,可作为大麦抗旱育种、抗旱机理及干旱调控缓解机制研究的材料。株高和总干重可作为评价大麦种质资源苗期抗旱性鉴定的性状指标。

Drought is the important abiotic stress factor for barley production in the northwestern hinterland.It is of great significance to identify drought resistance of barley resources,determine drought resistance index,screen drought resistance germplasm and cultivate drought resistance cultivars.The effects of the plant height,root length,leaf length,shoot fresh weight,root fresh weight,shoot dry weight,root dry weight and total dry weight of thirty barley germplasms were measured at the normal water supply and repeated drought treatments in pot experiments in rainprotection shed.Drought resistance comprehensive evaluation value(D value),comprehensive drought resistance coefficient(CDC value),weight drought resistance coefficient(WDC value),correlation analysis,frequency analysis,principal component analysis,grey relational analysis,subordinate function analysis,clustering analysis,and stepwise regression analysis were used to identify the drought resistance and screen drought resistance indices of tested barley germplasms at seedling stage.The results showed that drought stress had significant effects on all indices.Frequency analysis showed that the sensitive degrees of all indices response to drought stress in turn for root length,root dry weight,total dry weight,shoot fresh weight,shoot dry weight,leaf length,root fresh weight and plant height.Correlation analysis showed that the total dry weight was significantly and positively correlated with root dry weight,shoot dry weight,leaf length,root length and shoot fresh weight,but not with plant height and root fresh weight.Principal component analysis showed that 4 principal components could represent 83.583%of the original data information of barley drought resistance.The ranks of drought resistance of tested barley germplasms based on the D value,CDC value,and WDC value were similar.Grey relational analysis showed that the correlation degree between DC value of all indices and D value in turn for plant height,shoot dry weight,total dry weight,leaf length,shoot fresh weight,root length,root dry weight and root fresh weight,which was basically consistent with the order of correlation degree between DC value and WDC value.According to D value clustering analysis,tested barley germplasms were divided into 5 drought resistance grades,2 belonged to grade 1,13 belonged to grade 2,6 belonged to grade 3,7 belonged to grade 4,and 2 belonged to grade 5.The subordinate function values of tested indices except for root fresh weight,shoot dry weight,root dry weight and total dry weight,CDC value,D value,and WDC value were increased with increase of drought resistance grades.Stepwise regression analysis showed that the plant height and total dry weight were closely related to the D value.Xizang 25 and NEVADA were identified as drought resistance barley germplasms at seedling stage,which could be used as materials for the researches on cultivar breeding,mechanism,and regulation and alleviation mechanism of drought resistance in barley.The plant height and total dry weight could be used as the simple and intuitive identification indices of drought resistance in barley germplasm resources at seedling stage.