利用SNP标记及配合力划分超甜玉米自交系的杂种优势群

Classifying Heterotic Groups of Super-sweet Corn Inbred Lines by Combining Ability and SNP Markers

划分超甜玉米自交系的杂种优势群,筛选配合力高的甜玉米自交系,构建新的杂种优势更强的甜玉米群体,为优良甜玉米的选育提供依据。本研究选用23个自育超甜玉米自交系,采用NCⅡ设计得到60(3×20)个组合,研究它们的产量配合力效应并结合56K SNP标记将供试材料进行杂种优势群的划分。结果表明23个自交系的平均杂合率为2.59%,纯合度较高;除GX06和GX10,GX14和GX15,GX16和GX17的遗传相似度较高外,其余自交系之间的遗传相似度均小于90%,可作为不同的材料在育种上应用;测验系GX21和被测系GX01、GX03、GX12、GX13、GX18的产量GCA正向效应值较高,在产量性状上是非常优良的自交系;进化树、主成分分析和产量SCA聚类图将23个超甜玉米自交系分为GX21群、GX22群和GX23群,其中GX22(HJZ33)群称为父本群,包含的自交系为GX02、GX11、GX19、GX20及测验系GX22自身共5个,GX21(GTL273)和GX23(YC26)群称为母本群,包含的自交系为GX01、GX03~GX10、GX12~GX18及测验系GX21和GX23共18个。SNP标记和产量SCA分群结果基本一致,使用SNP标记化划分杂种优势群可以明显缩短玉米育种周期。

Classifying heterotic groups of super-sweet corn inbred lines,selecting inbred lines of high combining ability and constructing new stronger heterotic groups could provide basis for breeding excellent sweet corns.23 self-bred super-sweet corn inbred lines were used to make up 60(3×20)hybrid combinations with NCⅡdesign to classify heterotic groups by analyzing the combining ability of yield and 56 K SNP markers.The results indicated that the average heterozygosity of 23 inbred lines was 2.59%,and the homozygosity was higher.Except for GX06 and GX10,GX14 and GX15,GX16 and GX17,the genetic similarity between the inbred lines was less than 90%,which could be used as different inbred lines in breeding.The positive effect value of GCA in yield of the tester line GX21 and the tested lines GX01,GX03 GX12,GX13,GX18 was higher and they were excellent inbred lines.The results of evolutionary tree,PCA and clustering diagram of SCA classified the 23 super-sweet corn inbred lines into GX21 group,GX22 group and GX23 group.GX22(HJZ33)group was named the male parent group,including 5 inbred lines(GX02,GX11,GX19,GX20 and the tester line GX22),GX21(GTL273)and GX23(YC26)groups were named the female parent groups,including 18 inbred lines(GX01,GX03-GX10,GX12-GX18 and the tester lines GX21 and GX23).The results of SNP markers agreed with SCA of yield basically and using SNP markers to classify heterotic groups could shorten the corn breeding cycle significantly.