Molecular mapping of QTLs for resistance to northern corn leaf blight in maize.

摘要

The objectives of this study were to identify RAPD and ISSR markers linked to northern com leaf blight (NCLB) resistant genes in F2 population of maize using bulked segregant analysis and to map NCLB resistance genes in F2 populations of maize. The F2 white population of maize was developed from a cross between the resistant line Sd-63 and the susceptible line Sd-7. Bulked segregant analysis with RAPD and ISSR markers was conducted to identify markers that were linked to the Ht1 gene. The linkage relationship between the RAPD markers (Pr11_180bp, Pr11_300bp and OPB08_290bp) and northern com leaf blight resistance (NCLB) Ht1 gene were estimated using F2 population derived from the cross Sd63 x Sd7. The genetic distances between RAPD markers (Pr11_180bp, Pr11_300bp and OPB08_290bp) and NCLB resistance Ht1 gene were determined to be 25.4, 17.5 and 9.6 cM, respectively, with LOD scores of 38.9, 38.5 and 56.5, respectively. Therefore, RAPD markers (Pr11_180bp, Pr11_300bp and OPB08_290bp) were linked to the quantitative trait loci (QTL) for (NCLB) resistance Ht1 gene. The genetic distance between ISSR markers (AD1_820bp and AD6_650bp) and NCLB resistance Ht1 gene were determined to be 7.4 and 3.3 cM, respectively, with LOD scores of 49.1 and 51.8, respectively. Therefore, ISSR markers (AD1_820bp and AD6_650bp) were linked to the quantitative trait loci (QTL) for NCLB resistance Ht1 gene. The present study indicated that RAPD and ISSR markers, combined with bulked segregant analysis, could be used to identify molecular markers linked to NCLB resistance gene in maize. Once these markers are identified, they can be used in maize breeding programs, as a selection tool in early generations.