中华猕猴桃不同倍性间杂交后代倍性分离和遗传变异分析

Analysis of Ploidy Segregation and Genetic Variation of Progenies of Different Interploidy Crosses in Actinidia chinensis

了解不同倍性间杂交后代的倍性分离及其遗传分化规律对定向育种、多倍体种质创制及理论创新具有重要意义。利用流式细胞仪及AFLP分子标记检测不同倍性的8个中华猕猴桃杂交组合群体子代倍性分离及遗传分化规律。结果表明:六倍体母本‘新观2号’与二倍体父本‘红阳’雄系和‘桂海’雄系杂交子代群体创制出新的倍性个体(3x、4x、5x、7x、8x),且杂交组合群体的遗传多样性(H:0.4166和0.4305)、Shannon信息指数(I:0.5833和0.6053)、多态位点百分率(P:91.18%和92.63%)均显著高于其他组合;而倍性差较小的4个杂交组合[4x(♀)×6x(♂)、4x(♀)×2x(♂)、4x(♀)×2x(♂)和2x(♀)×4x(♂)],其基因多样性(0.3174、0.3346、0.3276和0.3198)、Shannon信息指数(0.4269、0.4568、0.4420和0.4445)、多态位点百分率(71.27%、76.14%、74.72%和75.84%)水平相对较低,且创制出奇数倍性个体(5x、3x、3x)。进一步遗传分析表明,除6号杂交组合[4x(♀)×2x(♂)]外,绝大部分杂交组合的后代群体与母本具有更近的遗传距离。

Understanding ploidy segregation and genetic divergence of interploidy hybrids is useful for directional selection, creating polyploidy germplasm and exploring theoretical population genetics. Flow cytometry and AFLP molecular markers to be used explore ploidy segregation and genetic differentiation of hybrid progenies of eight crosses with different ploidy parents in Actinidia chinensis complex. The results showed that crosses between hexaploid females ＇Xinguan 2＇ and diploid males ＇Hongyang＇ （ ♂ ） and ＇Guihai＇ （ ♂ ） created hybrids with new ploidy levels （3x, 4x, 5x, 7x, 8x） .Moreover, the Nei＇sgeneticdiversity （H. 0.4166, 0.4305）, Shannon index （I： 0.5833, 0.6053）and percentage of polymorphic loci （P： 91.18%, 92.63%） were higher than other crosses. Crosses with lower interploidydifference[4x（♀）×6x（6）、4x（♀）×2x（♂）、4x（♀）×2x（♂）和2x（♀）×4x（♂）] have relatively lower genetic variation in the progenies, but created hybrids with odd number of ploidy levels （5x, 3x, 3x）. Progeny populations of all crosses showed a number of novel bands. Further analysis of genetic distance showed that, except for the cross No. [4x（♀）×2x（♂）] closer genetic relationships between offsprings and the female parents were revealed in all other crosses.