栗属杂交F1代生长与枝条性状遗传变异及杂种优势分析

Genetic Variation and Heterosis Analysis of Growth and Shoot Traits in F1 Progeny of Chestnut Hybrids

为探索栗属杂交F1代幼林期生长、枝条性状遗传变异规律及杂种优势,并为栗属育种亲本选配及早期选择指标筛选奠定理论基础,该研究以锥栗、板栗种内和种间9个杂交组合子代及其亲本为材料,在分析F1代幼林期生长、枝条性状遗传变异规律及杂种优势的基础上,利用SSR分子标记检测7个亲本的遗传距离,进而分析栗属杂交子代生长、枝条性状杂种优势与亲本遗传距离间的关系。结果显示:(1)栗属杂交F1代生长、枝条性状均存在较高的遗传变异,各性状组合间F值的变动范围为5.08~22.03,组合内的变异系数范围为6.60%~27.69%;各性状广义遗传力均在0.5以上,性状受遗传影响较大;除地径外,其他性状遗传传递力均大于100%,性状遗传稳定性较高;各性状中亲优势率为-6.01%~44.40%,且F1代生长、枝条性状存在普遍的超亲分离现象。(2)28对引物在7个亲本中共检测出115个多态性等位位点,每对引物的等位基因数3~5个不等,平均每对引物等位基因数为4.1个,多态性程度较高;Shannon's指数(I)、多态性信息含量(PIC)的平均值分别为1.25、0.674,亲本遗传多样性较为丰富。(3)相关分析表明,杂交子代一年生枝长、一年生枝粗及节间距的杂种优势与亲本遗传距离均存在显著的线性关系,并随遗传距离增大杂种优势增强。

To explore the genetic variation and heterosis of growth and shoot traits of F1 progeny of Castanea during young forest stage and lay a theoretical foundation for parent selection and early selection index screening of Castanea,we used the progenies of 9 combinations(interspecific and intraspecific cross between C.mollissima and C.henryi)and their parents as materials to analyze the genetic variation and heterosis of growth and shoot traits in study.Meanwhile,The genetic distance among 7 parents was detected by SSR molecular markers,which was used to analyze the relationship between the heterosis of growth and shoot traits and genetic distance of parents.Results showed that:(1)there was a high genetic variation among growth and shoot traits for F1 progeny of Castanea.The variation range of F value about traits was 5.08-22.03 among combinations,and the variation coefficient within combinations ranged from 6.60%to 27.69%.The general heritability of each trait is above 0.5,except for ground diameter,the inheritance of transfer ability of other traits were all above 100%,which indicated that the traits were greatly influenced by heredity and high genetic stability.The mid-parent heterosis rate of each trait ranged from-6.01%to 44.40%,and there was a general superparental separation phenomenon of F1 progeny of chestnut hybrids in growth and shoot traits.(2)A total of 115 polymorphic allelic loci were detected from 7 mating parents in 28 SSR markers.The number of allelic loci per SSR markers ranged from 3 to 5,and the average was 4.1.The mean of Shannon's index(I)and polymorphism information content(PIC)were 1.25 and 0.674,respectively,which reveal that the genetic diversity were abundant in parents.(3)There was a significant linear relationship between the heterosis of annual branch length,diameter,node spacing and genetic distance of parents,and the genetic distance increased with the increase of heterosis.