62份陆地棉种质资源苗期抗旱性综合评价及耐旱种质筛选

Comprehensive identification and selection of drought resistance of 62 cotton varieties(lines)at cotton seedling stage

研究不同棉花品种(系)苗期对干旱引发渗透胁迫的适应性反应,通过多指标鉴定和综合评价苗期棉花供试品种(系)抗(耐)旱性,分析耐旱材料和干旱敏感材料苗期的植株和根系形态变化,为进一步提高棉花抗(耐)旱育种早代选择提供依据。采用15%PEG 6000营养钵砂培法对62份陆地棉种子进行苗期抗(耐)旱性鉴定筛选,分别测定在胁迫条件下以及对照条件下的棉花苗期植株形态、根部形态、以及生物量等18个抗(耐)旱相关指标,利用因子分析、隶属函数分析和聚类分析等方法对苗期的18项相关指标进行抗(耐)旱性综合评价。结果表明,这18个指标在15%PEG 6000(-0.4 MPa)胁迫条件下,除根冠比和根全长外其他指标均比对照显著降低,说明棉花苗期生长受PEG 6000的抑制,且根系受抑制程度低于地上部植株。通过对这18个指标的处理相对值进行因子分析,抗(耐)旱指标简化可得到6个主因子,包含根部投影面积、根像素面积、根表面积、根部体积等16个指标,其贡献率分别为35.01%、16.53%、12.46%、8.99%、6.60%、6.31%。利用这16个指标对62份陆地棉新材料进行隶属函数分析和相关性分析,并以平均隶属函数值代表抗(耐)旱性强弱,平均隶属函数值越大,抗(耐)旱性越强,结合品种聚类分析结果选出相对抗旱品系7个、相对耐旱品系4个、敏感品系6个;45份材料介于耐旱与敏感之间的过渡类型。

The purpose of this study was to study the adaptive response of different cotton varieties(lines)to drought induced osmotic stress at seedling stage.To improve selection of early generation of cotton drought resistance breeding,drought resistance of cotton varieties(lines)by multi index identification and comprehensive evaluation,morphological changes of plants and roots of drought tolerant materials,and drought sensitive materials at seedling stage were analyzed.The drought resistance of 62 upland cotton varieties(lines)at seedling stage was identified and selected by 15%PEG 6000 nutritive cube sand substrate culture method.18 drought resistance related indexes,including plant morphology,root morphology and biomass,were measured under PEG(polyethylene glycol)stress and control conditions.The 18 drought resistance indexes at seedling stage were analyzed by factor analysis,membership function analysis and cluster analysis.The results showed that under 15%PEG 6000(-0.4 MPa)stress,all the 18 indexes except root shoot ratio and root length were significantly lower than the control group,indicating that the growth of cotton seedling was inhibited by PEG 6000,and the inhibition degree of root was lower than that of aboveground plants.Six main factors were obtained through simplification of the factor analysis,include 16 indexes such as root projection area,root pixel area,root surface area and root volume,with contribution rates of 35.01%,16.53%,12.46%,8.99%,6.60%and 6.31%,respectively.The 16 indexes were used to analyze the membership function and correlation of 62 upland cotton new materials,and the average membership function value represented the drought resistance.The larger the average membership function value was,the stronger the drought resistance was.Combined with the results of variety cluster analysis,7 relative drought resistant lines,4 relative drought tolerant lines,and 6 drought sensitive lines were identified.The drought stress level for the rest of 45 lines was between drought tolerant and drought sensitive.