紫薇异倍体的杂交亲和性分析及子代倍性鉴定

以二倍体红薇(H,2n)、三倍体紫薇(Z,3n)、四倍体紫薇(Z,4n)及四倍体银薇(Y,4n)为试材,进行杂交试验,检测紫薇异倍体杂交的亲和性,并采用细胞学倍性鉴定法对杂交子代的倍性进行鉴定和比较。结果显示:不同杂交组合子代的结实特性以及种子的出苗率均存在差异,其中Z(4n)×H(2n)的单果重(0.22 g)、单果种子数(40.1)、千粒重(1.79 g)及出苗率(36.4%)均高于H(2n)×Y(4n),且差异达到显著水平,表明在二倍体与四倍体的杂交中,四倍体作为母本的亲和性更高;H(2n)×Z(3n)后代倍性主要为非整倍体,占80%以上,其次是2n,占11.8%;Y(4n)×H(2n)后代倍性主要为3n,占50%,其次是非整倍体,占40%;H(2n)×Z(3n)后代中,1株为3n,2株为非整倍体;Y(4n)×H(2n)后代中,6株为3n,3株为非整倍体;H(2n)×Y(4n)后代幼苗中,1株为2n,1株为3n;Z(4n)×Z(4n)后代中,1株为4n;在杂交组合H(2n)×Z(3n)、Y(4n)×H(2n)及H(2n)×Y(4n)后代中还出现三子叶变异的幼苗。

The crossability and progeny ploidyidentification of hybridization among the heteroploidincrape myrtle

In the present study, we used H(2n), Z(3n), Z(4n ) and Y(4n) as the parents of hybridization to indicated the crossing-compatibility between them and identify the ploidy of offspring by cytological examination. The results suggested that there are obvious differences on fruiting and sprout among them. Capsule weight(0.22 g), seeds per capsule(40.1), thousand seed weight(1.79 g) and germination rate(36.4%) in the hybridization between Z(4n) and H(2n) were significantly higher than that of hybridization between H(2n) and Y(4n), which suggested the crossing- compatibility of 4n×2n was higher than the reciprocal cross. Most of lines in the progeny of H(2n)×Z(3n) were aneuploidy(80%)with a little diploid(11.8%); 50% lines in the progeny of cross Y(4n)×H(2n) were triploid, and 40% were aneuploidy. In the seedlings of cross H(2n)×Z(3n), 1 seedling was identified as 2n, 2 seedlings were aneuploidy; in the cross Y(4n)×H(2n), 6 seedlings were triploid, 3 seedlings were aneuploidy; in the cross H(2n)×Y(4n), 1 seedling as diploid, 1 seedling as triploid; in the cross Z(4n)×Z(4n), 1 seedling as tetraploid. Besides, tricotyledon mutant seedlings were founded in the cross of H(2n)×Z(3n), Y(4n)×H(2n) and H(2n)×Y(4n).