Articles

Analyses of genetic diversity among exotic- and indigenous- maize inbreds differing for responses to stored grain weevil (Sitophilus oryzae L) infestation


Abstract


Sitophilus oryzae has emerged as one of the important storage grain pests of maize especially in Asia. It causes damage to the stored grains and affects significantly its quality and viability. A set of 48 diverse maize inbreds dif- fering for degree of resistance against S. oryzae were analyzed for genetic diversity using 63 SSRs spread across the genome. The study generated a total of 177 alleles, with two to six alleles per locus. Seven unique and 13 rare alleles were detected among the inbreds. Polymorphism information content ranged from 0.04 to 0.67, and Jaccard’s dissimilarity coefficient varied from 0.32 to 0.77 with a mean of 0.62. The cluster analyses grouped the genotypes into three major clusters, and the principle coordinate analysis revealed diverse nature of the inbreds across four quadrangles. Genetically distant resistant inbreds identified in the study can be used for generating heterotic cross combinations with resistance to S. oryzae. These diverse resistant inbreds can also be used for generating pools and segregating populations to derive new inbreds with improved resistance. Mapping popula- tions developed from genetically diverse and phenotypically contrasting inbreds would help in identifying QTLs imparting resistance to infestation of S. oryzae. Genomic regions thus identified would help in improving the de- gree of resistance in susceptible maize through marker-assisted selection.

Keywords

maize, stored grain weevil, Sitophilus oryzae, resistance, SSR markers

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