利用SSR标记进行玉米品种一致性检测研究

Uniformity Analysis of Maize Varieties by a Set of SSR Markers

为了评估SSR标记在玉米品种一致性鉴定中的应用价值及确定基于SSR标记的玉米一致性鉴定标准,利用13个SSR标记对213份来自2004年国家区域试验的玉米单交种(包括16份重复材料)进行了一致性分析,每个品种取20个个体,除在染色体6和8上各选取了2个和3个标记外,其他染色体上均各选取1个SSR标记。结果显示:一致性检测中异型带的类型有7种,每种出现的概率不同;不同品种在不同引物位点的一致性分布情况差别较大。比较位于同一染色体的引物一致性检测结果,发现在相同染色体上位置较近的不同引物一致性检测结果具有较高的相关性,因此提出在选用一致性检测的引物时应遵循均匀分布的原则,减少引物间的相关性。通过剔除自交个体对品种一致性比率进行校正(仅有7个品种),校正值可反映品种真实的遗传一致性和稳定性。综合考虑品种在单个引物位点的一致性和在所有位点的平均一致性,提出了划分玉米品种一致性级别的标准。

The aim of this study was to evaluate the availability of SSR markers for variety uniformity testing in maize hybrids and trying to bring forward a standard for variety uniformity testing by SSR markers. For this purpose, a set of 13 SSR primers were used to analyze 213 maize single hybrids （20 individuals per variety） from national regional trial in 2004, containing 16 duplicates. One SSR marker per chromosome was selected except 2 markers in chromosome 6 and 3 markers in chromosome 8. Seven band types between normal and anomalous bands were found in uniformity testing, but the frequency of each type varied. Uniformity distribution was quite uneven among different varieties and different SSR loci; a comparison of uniformity between SSR loci at the same chromosome and at different chromosome were conducted and the results showed that there had certain relativity at different loci of the same chromosome, especially high at the same chromosome bin because of interlock be- tween the loci. The uniformity ratio of 7 accessions were corrected by subtracting selfed individuals, the corrected ratio could reflect the true genetic uniformity of a variety. After taking account of both uniformity value at single SSR loci and average uniformity value at all the SSR loci, the standard of uniformity （divided into 5 levels） in maize variety was suggested, which was different from that in morphological uniformity testing.