中国328个玉米品种(组合)SSR标记遗传多样性分析

Genetic Diversity Analysis of 328 Maize Varieties(Hybridized Combinations)Using SSR Markers

【目的】从育成年份、种植区域角度分析中国328个玉米品种的遗传多样性,在分子水平上分析各适宜种植区域品种的遗传分化特点,为玉米品种区域试验、审定管理以及育种策略提供一定的理论依据。【方法】利用均匀分布于玉米基因组的40对核心SSR引物,采用10重荧光毛细管电泳检测技术对328个代表性育成品种进行基因分型;通过Power-Marker ver.3.25软件评估40对SSR引物多态性,对参试品种按年份、区试组分析遗传多样性情况;利用多变量统计分析软件MVSP ver.3.13对328个品种按区试组进行主坐标分析。【结果】基于328个玉米品种数据,检测到40对SSR引物等位基因变异范围为3—16个,平均8.10个,多态信息指数(PIC)值变化范围为0.18—0.85,平均为0.63。参试品种不同年份间遗传多样性变化不大,PIC值在0.60左右摆动;8个区试组品种的总等位基因和总基因型变异范围为170—262和200—511,京津唐和西南组分别表现出了最低值和最高值,京津唐组PIC值最低为0.51,其余组均接近于0.60,平均杂合度均在0.60左右。8个区试组主坐标分析显示鲜食、极早熟品种遗传分布偏离普通玉米区域,具有明显的种质特异性;青贮玉米由于早期对照品种为普通玉米导致遗传分布向普通玉米延伸,仅有少数品种分布偏离普通玉米;京津唐、西南、东北早熟三组品种遗传分布相对集中;极早熟、京津唐、西南三组之间品种遗传分布几乎无重叠区域;东华北和黄淮海两组参试品种遗传分布具有明显的分化但也有部分重叠,原因与对照品种曾经相同、育种同质化有关。【结论】利用SSR标记分析328份玉米品种的遗传多样性及遗传分化特点,表明近年来育成品种遗传多样性指数在不同年份间变化不大,除京津唐组之外在其它区试组间差异性也不大。参试品种主坐标分析显示各区试组划分、对照品种设置起到了育种导向的作用。

【Objective】 The objective of this study is to analyze the genetic diversity of 328 maize varieties from breeding years, planting regions, and to research the genetic differentiation characteristics of all the varieties from every appropriate planting region. This study will provide a theoretical basis for the maize regional trial, validation management and breeding strategic adjustment. 【Method】 Forty core SSR primers covering the entire maize genome were used to scan 328 samples by high-throughput 10-plex capillary electrophoresis platform. The polymorphism of 40 SSR loci and genetic diversity of 328 samples were evaluated via the software Power-Marker ver.3.25, and the Principal Coordinate Analysis （PCoA） of these samples from every regional trial groups was executed using statistical analysis software MVSP ver.3.13. 【Result】 The detected alleles of 40 SSR primers ranged from 3 to 16, with an average of 8.10, the polymorphism information index （PIC） ranged from 0.18 to 0.85, with an average of 0.63. There were no significant genetic diversity changes among varieties from different years, and all the PIC values were about 0.60. The total allele and gene-type number of 8 regional trial groups ranged from 170 to 262 and from 200 to 511. The varieties from Jing-Jin-Tang and Xi-Nan displayed the minimum and maximum values. The varieties from Jing-Jin-Tang group displayed the lowest PIC value of 0.51, and the remaining groups were near 0.60, and the average heterozygosity was about 0.60. Principal coordinate analysis （PCoA） of varieties from eight regional trial groups showed that the genetic distribution of varieties from Xian-Shi （maize for table use） and Ji-Zao-Shu （very early maturity maize） groups deviated from the common maize region, displayed an obvious germplasm specificity. As the common maize varieties were used as control samples at early stage, the genetic distribution of Qing-Chu （silage corn） extended to common maize. The genetic distribution of varieties from Jing-Jin-Tang, Xi-Nan and Dong-Bei-Zao groups was relatively concentrated. The genetic distribution of varieties from Ji-Zao-Shu, Jing-Jin-Tang and Xi-Nan groups was almost no overlap. There is an obvious genetic variation of varieties from Dong-Hua-Bei and Huang-Huai-Hai groups, but also there are some overlaps, and the reasons might be the same control variety and the same breeding resource. 【Conclusion】 Genetic diversity and genetic differentiation of 328 maize varieties were analyzed using 40 SSR markers. The results showed that there were no significant genetic diversity changes among varieties in different years, and there were also no significant changes among different groups except that from Jing-Jin-Tang. Principal coordinate analysis showed that the setting of regional trial groups and control varieties has played a guiding role in breeding.