不同棉花基因型根系表型差异分析

Analysis on Root Phenotype of Different Cotton Genotypes

根系是植物吸收水分和养分的主要器官,对根系表型进行分析,不仅有助于提高资源的利用效率,而且可以加速水分和养分高效吸收利用型种质的创新及新品种选育。本试验采用室内纸培法对88个不同基因型棉花种质进行培养,获得根系发育完全的幼苗,用Epson扫描仪投射扫描获得根系照片,然后利用Image J和WinRhizo软件得到了根系主要表型性状,并测量棉苗地上、地下部分干重,计算根冠比。经统计分析显示,除平均根夹角外,其他9个性状的变异系数均超过10%,说明参试棉花基因型的根表型存在丰富的遗传变异,改良潜力较大。相关分析表明根系表型性状之间存在信息重叠,经主成分分析可降维为3个主成分,累积贡献率为77.872%,包含了表型性状的绝大部分性状,其中,根表面积、总根长、侧根长、主根长、根体积、主根根尖区比例、平均根夹角及侧根密度是3个主成分的主导因子。依据上述结果进行聚类分析,可将88个参试棉花基因型分为5类,其中第Ⅳ类属于水氮高效基因型,第Ⅱ类属于磷、钾高效基因型。本研究结果可为棉花水肥高效利用种质的选育以及阐述其水肥高效吸收利用机制提供依据。

Root is the main organ for plants to absorb water and nutrients.Analysis of root phenotype not only is helpful to improve the utilization efficiency of resources,but also can speed up the innovation of germplasms and the breeding of new varieties with efficient absorption and utilization of water and nutrients.In this experiment,88 cotton germplasms with different genotypes were cultured in greenhouse by paper culture method.The seedlings with fully developed roots were obtained.Root photos were obtained by Epson scanner under projection scanning.Then,the root phenotypic traits were obtained by using Image J and WinRhizo software.The dry weight of cotton seedlings above and below ground was measured and the root-shoot ratio was calculated.Statistical analysis results showed that,except for the average root angle,the variation coefficient of the other 9 traits were all more than 10%,indicating that the root phenotype of the cotton genotypes participating in the experiment had abundant genetic variation and great potential for improvement.Correlation analysis showed that there was overlap of information between root phenotype traits.The principal component analysis showed that three principal components could be used to represent most of the phenotypic traits,and their cumulative contribution rate was 77.872%.Among them,root surface area,total root length,lateral root length,principal root length,root volume,proportion of apical region of taproot,average root angle and lateral root density had great contributions to the three dominant factors.Based on the above results,the 88 tested cotton genotypes could be divided into 5 clusters by cluster analysis.Among them,group Ⅳ was the water and nitrogen efficient type,and group Ⅱ was the phosphorus and potassium efficient type.These results could provide bases for breeding germplasms with efficient utilization of water and fertilizer,and elaborating the mechanism of efficient absorption and utilization of water and fertilizer in cotton.