Genetic diversity of maize germplasm lines and implications for breeding Maize streak virus resistant hybrids

Abstract

Evaluation of genetic distances between maize inbred lines can be used to maximise heterosis in hybrids. This study was conducted to determine genetic distances among 25 maize inbred lines in the Maize streak virus disease (MSVD) QTL region to develop MSVD-resistant hybrids. The inbred lines were genotyped using 19 simple sequence repeat (SSR) markers that are known to be associated with MSVD resistance in maize. All amplification products were in the range of 68–290 bp. In total, 94 SSR alleles were detected, with a mean of 4.95 alleles per locus. The average polymorphic information content value was 0.56. Gene diversity (H_е) values ranged from 0.00 to 0.853 with an average of 0.594, whereas heterozygosity (H_o) values attained an average of 0.039, ranging from 0.00 to 0.095. There were three major clusters and five subclusters, from which potential breeding lines could be sampled. These results confirmed the diversity found among the maize lines within the MSVD QTL region used in this study. In general, the grouping of the inbred lines by SSR markers is consistent with pedigree information. The data from SSR markers was useful in identifying lines that could be used to design new hybrids and new breeding populations for MSVD resistance.

Keywords: hybrid vigour, maize, molecular breeding, simple sequence repeats, SSRs

South African Journal of Plant and Soil 2014, 31(2): 77–86