花生巢式群体的脂肪含量遗传分析

Genetic analysis of fat content based on nested populations in peanut(Arachis hypogaea L.)

巢式群体可以利用多个亲本解析复杂性状的遗传机制。本研究利用1个共同亲本与6个基础亲本所配置巢式组合F_(2:3)家系的种子脂肪含量数据,分析了花生脂肪含量的遗传模型,旨在探明不同的基础亲本组合中脂肪含量性状的遗传差异,为制定脂肪含量遗传改良的亲本选配和后代选择策略提供依据。6个组合的共同亲本为高脂肪含量的普通型大果品种豫花15号,其他6个基础亲本为不同脂肪含量和不同植物学类型的品种。结果表明,在不同杂交组合中脂肪含量的遗传模式有所不同,6个组合分别符合无主基因模型、1对主基因加性显性模型和2对主基因等显性模型3种遗传模式。各种遗传效应的估计值也各不相同,主基因遗传力从32%到80%,说明不同杂交组合中,控制脂肪含量的基因位点差异及其重组和分离方式不同。高脂肪含量双亲杂交后代的高脂肪含量个体较多,但主基因遗传力较低,不宜在早代实施表型选择;双亲脂肪含量差异较大的后代脂肪含量变异幅度更大,能够选择到不同脂肪含量的类型。本研究也表明,巢式组合具有较丰富的脂肪含量变异类型,揭示出脂肪含量性状遗传的复杂性和多基因调控的特点,为较全面地了解脂肪含量的遗传提供了基础。该巢式群体也将有助于进一步开展脂肪含量的QTL定位研究。

Nested populations can be used to dissect the heredity of complex traits.The genetic models of fat content of F_(2:3)families in nested combinations with one common parent and six founder parents were analyzed,aiming to detect the genetic differences among the founders and to provide bases for breeding strategy for fat content improvement in peanut kernels.The common parent was Yuhua 15,an irregular-type variety with high fat content,and the other six founder parents were different botanical varieties with different fat contents.The results showed that the genetic model of fat content traits was different in different combinations.Six crosses were in accordance with three genetic patterns,including none major gene model,one major gene model with additive and dominant effect,and two major genes model with equal additive and dominant effect.The estimated values of various genetic effects were also different.The heritability of the main genes ranged from 32%to 80%,indicating that the gene loci controlling the fat content and their segregation patterns were different in different F_(2:3)populations.There were more individuals with high fat content in the offspring from combinations with both parents of high fat content.However,the heritability was low and phenotypic selections for fat content were not suggested in the early generations in such combinations.The offspring from combinations with parents of significantly different fat content had a larger variation range in fat content,and phenotypes with variable fat content were available.In this study,the large variances in the nested populations demonstrated the genetic complexity of fat content and the characteristics of multi major gene regulation.These results provide a comprehensive base for understanding the genetics and regulation of fat content,and the nested populations will be helpful in further QTL detection of fat content in peanut.