宁夏春小麦抗旱性的遗传多样性分析

Genetic diversity of spring wheat germplasm resources based on drought resistance in Ningxia

以宁夏春小麦育成品种、地方品种以及引进种质等共91份春小麦为材料,在干旱胁迫(雨养)和正常灌溉两种水分处理下,调查了11个农艺性状及其耐旱指数,计算其遗传多样性指数并进行聚类分析。结果表明:不孕小穗数的变异系数最高,干旱胁迫与正常灌溉条件下分别为63.5%和51.5%,穗叶距次之,干旱胁迫和正常灌溉条件下分别为36.9%和36.3%;产量的耐旱指数与株高、穗下节长、穗叶距的耐旱指数呈极显著负相关;不同性状的多样性指数差异较大,变化范围从0.99到2.48,平均为1.73,其中,不实小穗数的多样性指数最高,为2.48。根据表型性状将参试材料分为5个类群,其中第IV类群材料表现为对水分条件不敏感,适于在干旱条件下种植。总体来看,宁夏春小麦种质的遗传基础较狭窄,育种家应广泛搜集利用国内外小麦种质及小麦近缘物种,以拓宽现有种质资源的遗传基础,为选育突破性小麦品种奠定基础。

In order to provide a theoretical basis for wheat breeding against drought,11 agronomic traits of 91 spring wheat germplasm resources,including wheat varieties cultivars,landraces and introduced varieties,were used to analyze their genetic diversity,the drought index and the clustering study. Results showed that sterile spikelet per spike had the largest coefficients of variance( CV) of 63. 5% and 51. 5% under the conditions of drought stress and normal irrigation,followed by length from flag leaf pulvinus to spike base with CV of 36.9% and 36.3%,respectively. Correlation analysis of drought tolerance index( DTI) showed that DTI of the yield had significant negative correlations with the plant height,peduncle length and length from flag leaf pulvinus to spike base,respectively. Genetic diversity index( H') of DTI among different traits had a large range from 0.99 to 2.48,with an average value of 1.73. The false spikelet number had the largest H' of 2.48. Based on the phenotypic traits,all accessions could be clustered into five groups. Varieties from the fourth group were not sensitive to irrigation and may be suitable for cultivation in dryland. Overall,the genetic basis of Ningxia spring wheat is relatively limited. Therefore,breeders should widely collect and use germplasm resources and proximal species of wheat,broadening the genetic basis in order to lay the foundation for breeding of breakthrough cultivars.