| Summary: | Avoiding linkage drag of the resistance genes will facilitate the use of gene resources for rice breeding. This study was conducted to confirm the avoidance of linkage drag due to <i>Pi26</i> and <i>Pi25</i> blast resistance genes, and to analyze the association of <i>Pi26</i>, <i>Pi25</i>, <i>Pib</i> and <i>Pita</i> with quantitative trait loci (QTL) for yield traits. A recombinant inbred line population was derived from an <i>indica</i> rice cross Dan 71/Zhonghui 161. A linkage map consisting of 1219 bin markers, 22 simple sequence repeats and five gene markers was constructed. A total of 75 QTL were identified, including 2 for leaf blast resistance and 73 for eight yield traits. The two QTL for blast resistance were closely linked and located in the <i>Pi26</i> and <i>Pi25</i> regions, explaining 69.06 and 12.73% of the phenotypic variance, respectively. In a region covering <i>Pi26</i> and <i>Pi25</i>, QTL were detected for grain yield and its key components. The alleles for enhancing blast resistance and grain yield were all from Dan 71. Not only was the linkage drag due to <i>Pi26</i> and <i>Pi25</i> avoided, but the results also indicate that these resistance genes may be used for simultaneously enhancing blast resistance and grain yield in rice. In the <i>Pib</i> and <i>Pita</i> regions, QTL was not detected for blast resistance, but was for yield traits. In each region, the allele for improving trait performance was derived from the parent carrying the resistance allele. In addition, four QTL clusters for grain weight and size, <i>qGL4</i>/<i>qGW4.1</i>, <i>qGL11.2</i>/<i>qRLW11</i>, <i>qTGW11</i>/<i>qGW11</i> and <i>qGL12</i>/<i>qGW12</i>/<i>qRLW12</i>, were shown to be promising candidates for map-based cloning.
|
|---|