Molecular genetic distance and hybrid performance between Chinese and American maize (Zea mays L.) inbreds

Abstract

Development of superior hybrids depends on the identification and exploitation of heterotic groups based on divergent germplasms. The polymorphisms among 13 Chinese and 13 American parental maize inbreds were evaluated at 107 simple sequence repeat (SSR) loci. Grain yield of 169 F1 hybrids and corresponding molecular genetic distance (GD) for parents were partitioned into general and specific combining ability (GCA and SCA) and general and specific genetic distance (GGD and SGD), respectively. SSR data revealed that different geographic sources of inbreds were substantially divergent with several germplasm-specific alleles. GDs between Chinese and American inbreds showed greater mean values and narrower ranges than those within each set of inbreds. The parental inbreds were clustered into four groups. F1 performance was highly correlated with SCA for grain yield regardless of the type of cross. F1 performance and SCA were correlated with GD and SGD in hybrids created only with temperate inbreds. Maize superior hybrids were produced only by crosses of different germplasm with greater GDs. BSSS enhances the heterotic pattern with any other inbreds from China. Iowa Corn Borer Synthetic No. 1 (BSCB1) and CIMMYT Pool41 were new promising germplasms for establishment of potential heterotic patterns in the Chinese maize breeding program.