葡萄同源四倍体F2群体的遗传变异分析

Genetic Variation Analysis in F2 Population from Autotetraploid Grape Hybrid

多倍体杂交育种已成为葡萄新品种选育的重要途径,本研究使用20个形态学性状和25对SSR分子标记,对二倍体玫瑰香、四倍体玫瑰香、巨峰、四倍体玫瑰香与巨峰杂交F1巨玫和F2群体进行遗传变异分析。形态学性状分析表明,在F2群体中14个形态学性状变异系数高于20%,F2群体平均Shannon信息指数为1.14,平均Nei′s遗传多样性指数为0.62,群体有丰富的遗传多样性。性状之间表现出显著的相关性,幼叶叶背绒毛密度与新梢节间绒毛密度(r=0.203)极显著相关,与成龄叶下表面绒毛密度(r=0.128)显著相关,主成分分析可以在二维上直观反映出F2单株与亲本表型的相似程度。25对SSR标记共扩增出127条带,平均多态性信息含量(PIC)为0.26,后代群体平均Shannon信息指数为0.49,平均Nei′s遗传多样性指数为0.32。形态学性状和SSR聚类分析发现,F2群体中大部分单株与F1巨玫相似,同时也出现一些与父母本遗传距离较远的单株,为未来葡萄四倍体品种选育提供了良好材料。

Breeding for tetraploid hybrids has become an optimal strategy in grape breeding.In the present study,we deployed 20 morphological traits and 25 simple sequence repeat(SSR) markers to access the genetic diversity of 278 genotypes.These materials contained four grape varieties(Muscat Hamburg,tetraploid Muscat Hamburg,Kyoho and Hybrid F1 Jumei by crossing of Kyoho and tetraploid Muscat Hamburg) and 274 individuals from Jumei′s F2 population.The morphological variation analysis revealed the average Shannon information index and the average Nei′s genetic diversity index of 1.14 and 0.62,respectively.The coefficient of variation of 14 traits was higher than 20% and significant correlations were found among some characteristics.Prostrate hairs density of lower side of young leaf was significantly positively correlated with Hairs density on internode of shoot(r=0.203) and Prostrate hairs density of lower side of mature leaf(r=0.128).By principal component analysis(PCA) and cluster analysis,the morphological traits showed eight principal components(PC1-PC8) explained approximately 60.99% of the total variance of the 278 genotypes,and the first three major PCs contributed to approximately 30.08%.The two-dimensional graph of PC1 and PC2 directly reflected the similarity between the phenotype of F2 population and its parents.The cluster analysis of 278 materials based on 20 morphological traits resulted in four main groups.Further genetic variation and diversity evaluation in 278 grapes materials was done using 25 SSR markers.127 bands totally were generated by 25 SSR markers using PCR amplifcation,including 52 polymorphic fragments.SSR analysis indicated,in the population,the average polymorphism information content(PIC) value was 0.26,the average Nei′s genetic diversity index was 0.32,and the average Shannon information index was 0.49.The result showed that these SSR markers were able to distinguish genetic variation among genotypes.The SSR cluster analysis based on UPGMA illustrated that the similarity coeffcient ranged from 0.38 to 1.00 and cluster analysis in 0.47 similarity coeffcient can divide 278 grapes genotypes accessions into five groups These results based 20 morphological traits and 25 SSR markers would be valuable for genetic diversity analysis and helpful in breeding selection.PCA and clustering analysis revealed that most of tetraploid F2 individuals were similar to Jumei(F1).The remaining individuals showed genetic differentiation with their parents,and they served as good materials for future selection and breeding for new tetraploid grape varieties.