SSR Heterogenic Patterns of Maize Parental Lines and Prediction of Hybrid Performance

Abstract

ABSTRACTTo investigate the potential of molecular markers in predicting hybrid performance, a set of 58 inbred lines were analyzed using 80 SSR primer pairs. The correlation between genetic divergence of inbred lines and the performance of hybrids was analyzed in the three sets of crosses including an 8x8 Diallel, a 6x6 Line x Tester (LxT) and testcross of all the inbreds with two testers. The crosses along with their respective parental lines were individually evaluated on alpha-lattice designs with two replications at two environments. Pair-wise genetic distance (GD) was estimated based on Jaccard, and simple matching (SM) coefficients. Significant correlation was found between GD value of parental lines and hybrid performance for the testcross and diallel data. In diallel analysis significant correlation was observed between total grain yield per ear (TGW) and genetic distance based on SM coefficient, whereas the correlation of GD and specific combining ability of hybrids for this trait was not. Through the stepwise multiple regression analysis a total of 19 informative SSR markers distributed over all chromosomes, except chromosomes 7 and 8, were detected. GD values based on informative markers in general were grater compared to that of based on all markers and significant improvement was observed in the correlations between GD estimates based on informative markers and TGW as well as SCA. Partitioning of genetic distances into general GD (GGD) and specific GD (SGD) revealed a large positive or negative GGD. It was found that GGD accounted for more variation of GD in comparison with SGD. Simple correlations between SGD for different measures and TGW as well as SCA were low and non-significant. This could be probably attributed to non-significant SCA of TGW, besides lower contribution of SGD to total GD variance.