Mapping genomic regions for red flour beetle (Tribolium castaneum (Herbst)) resistance in teosinte (Zea mays L. subsp. parviglumis H. H. Iltis & Doebley) derived maize backcross inbred line population

Abstract

The development of maize germplasm with resistance to red flour beetle requires identification of donors of resistant traits and understanding of the genetic mechanisms underlying resistance. As resistance sources are scarce in elite maize lines, teosinte (Zea mays ssp. parviglumis; 2n = 20) following insect bioassay was found to be resistant and therefore used as parent in a cross with flour beetle susceptible but superior maize inbred line DI-103 for development of backcross inbred line (BIL) mapping population with a view to identify genomic regions conferring resistance. Data on four resistance parameters namely, weight loss (WL), number of insect progeny emerged, kernel damage (KD) and flour produced (FP) were collected on 141 BILs. Highly significant differences were found amongst BILs for all the parameters indicating substantial variability in the population for the traits probably contributed by teosinte. Based on cumulative susceptibility index (CSI), 83 BILs were scored as resistant and can be utilized as donor for flour beetle resistance in maize improvement programs. Principal component analysis was conducted and first three principal components contributing 92.36% of the total phenotypic variation were identified. Highly significant positive correlations were found between all trait combinations except for correlation between WL and KD which was positive but non-significant. A total of 18 marker linked genomic regions were found to be significantly associated with red flour beetle resistance. Two major quantitative trait loci (QTLs) were detected on chromosome 1 and 3 for KD and they explained 11.17% and 14.88% of the total phenotypic variation, respectively. Highest number of colocalized QTLs i.e., 3 were detected for KD and FP. These linked markers after further validation can be used in future for indirect selection for resistance to red flour beetle in maize.