King Saud University, College of Science, Saud Arabia.
El Fayoum University, College of Science, Egypt.
Braz J Biol. 2021 Jul-Sep;81(3):601-610. doi: 10.1590/1519-6984.226889.
The present study aimed to assess population structure and phylogenetic relationships of nine subspecies of Brassica rapa L. represented with thirty-five accessions cover a wide range of species distribution area using isozyme analysis in order to select more diverse accessions as supplementary resources that can be utilized for improvement of B. napus. Enzyme analysis resulted in detecting 14 putative polymorphic loci with 27 alleles. Mean allele frequency 0.04 (rare alleles) was observed in Cat4A and Cat4B in sub species Oleifera accession CR 2204/79 and in subspecies trilocularis accessions CR 2215/88 and CR 2244/88. The highest genetic diversity measures were observed in subspecies dichotoma, accession CR 1585/96 (the highest average of observed (H0) and expected heterozygosity (He), and number of alleles per locus (Ae)). These observations make this accession valuable genetic resource to be included in breeding programs for the improvement of oilseed B. napus. The average fixation index (F) is significantly higher than zero for the analysis accessions indicating a significant deficiency of heteozygosity. The divergence among subspecies indicated very great genetic differentiation (FST = 0.8972) which means that about 90% of genetic diversity is distributed among subspecies, while 10% of the diversity is distributed within subspecies. This coincides with low value of gene flow (Nm = 0.0287). B. rapa ssp. oleifera (turnip rape) and B. rapa ssp. trilocularis (sarson) were grouped under one cluster which coincides with the morphological classification.
本研究旨在利用同工酶分析评估 35 个代表甘蓝型油菜 9 个亚种的材料的种群结构和系统发育关系，以选择更多不同的材料作为补充资源，用于油菜的改良。酶分析共检测到 14 个假定的多态性位点，有 27 个等位基因。在亚种甘蓝型油菜 CR 2204/79 中的 Cat4A 和 Cat4B 以及亚种黑芥型油菜 CR 2215/88 和 CR 2244/88 中的等位基因 0.04（稀有等位基因）。亚种二色型油菜 CR 1585/96 的遗传多样性最高（最高的观测平均（H0）和期望杂合度（He），以及每个位点的等位基因数（Ae））。这些观察结果使该材料成为一个有价值的遗传资源，可被纳入油菜的改良的育种计划中。固定指数（F）的平均值显著高于零，这表明杂合性明显不足。亚种间的分化表明遗传分化非常大（FST = 0.8972），这意味着大约 90%的遗传多样性分布在亚种之间，而 10%的多样性分布在亚种内。这与基因流（Nm = 0.0287）的低值相吻合。甘蓝型油菜亚种甘蓝型油菜（芜菁）和甘蓝型油菜亚种黑芥型油菜（芥菜）被归为一组，这与形态分类一致。
