水稻核心种质表型性状遗传多样性分析及综合评价

Analysis on Genetic Diversity of Phenotypic Traits in Rice(Oryza sativa)Core Collection and Its Comprehensive Assessment

种质资源是水稻遗传育种和解析复杂性状的重要基础,而对遗传多样评估有利于鉴定最优亲本组合,以产生遗传变异最大的后代群体和促进不同资源的有利基因渗透到栽培品种。选用14个表型性状对美国农业部水稻核心种质中的六大洲1579份水稻种质,分析与评价其遗传多样性和优良稻种资源,主要结果如下:(1)亚洲、非洲与大洋洲种质间遗传距离较远,且亚洲、非洲和大洋洲的水稻资源具有较丰富的表型遗传多样性,而不同性状的遗传多样性在洲际间表现不同;粒长宽比、碱消值、株高、粒宽、千粒重和淀粉含量6个性状具有很高的表型遗传多样性。(2)采用主成分分析法和逐步回归分析法综合评判表明,越南的PI392768的综合性状表现最好,法国的PI281760综合性状表现最差,同时淀粉含量、抽穗期、株高、倒伏性、糙米色和颖壳色6个性状可作为种质资源综合评价指标。在水稻育种中应注重利用具有丰富遗传多样性的种质资源,并在亲本选配时适当选择遗传距离较远且综合性状表现差异大的种质材料。

Germplasm resources are fundamental in rice breeding and dissecting complex traits.Assessment of genetic diversity benefits the identification of optimal parental combinations to produce segregating offspring with maximum genetic variability,and facilitates the introgression of favorable genes from various germplasm into commercial cultivars.The USDA rice core collection（USDA-RCC）（1 579 rice accessions originated from six continents）,was analyzed with 14 phenotypic traits to assess diversity and phenotypically superior rice germplasm.The main results were summarized as follows：（1）Genetic distance of the germplasm from Asia and Africa to that of Oceania was larger.Rice germplasm from Asia,Africa and Oceania had accordingly greater phenotypic and genetic diversities,and genetic diversity of different traits was different among continents.Six traits including kernel length/width（KLW）,alkali spreading value（ASC）,plant height（PH）,kernel width（KW）,1000-kernel weight（TKW）and amylose content（AC）had greater genetic diversity.（2）Comprehensive assessment of phenotypic traits was conducted using principal component analysis（PCA）and step regression analysis,demonstrating that the accession PI 392768 from Vietnam had the best comprehensive traits while the accession PI 281760 performed the worst comprehensive traits;AC,HD,PH,lodging,BRC,and HC would be suitable as comprehensive criteria for assessing USDA-RCC germplasm.We suggest these rice germplasm possessing great phenotypic diversity should be widely utilized in breeding programs,moreover,these rice germplasm with farther genetic distance and different comprehensive traits should be appropriately considered for the parental selection.