Molecular Mapping of Reduced Plant Height Gene Rht24 in Bread Wheat

Abstract

Height is an important trait related to plant architecture and yield potential in bread wheat (<i>Triticum aestivum</i> L.). We previously identified a major quantitative trait locus <i>QPH.caas-6A</i> flanked by simple sequence repeat markers <i>Xbarc103</i> and <i>Xwmc256</i> that reduced height by 8.0-10.4%. Here <i>QPH.caas-6A</i>, designated as <i>Rht24</i>, was confirmed using recombinant inbred lines (RILs) derived from a Jingdong 8/Aikang 58 cross. The target sequences of <i>Xbarc103</i> and <i>Xwmc256</i> were used as queries to BLAST against International Wheat Genome Sequence Consortium database and hit a super scaffold of approximately 208 Mb. Based on gene annotation of the scaffold, three gene-specific markers were developed to genotype the RILs, and <i>Rht24</i> was narrowed to a 1.85 cM interval between <i>TaAP2</i> and <i>TaFAR</i>. In addition, three single nucleotide polymorphism (SNP) markers linked to <i>Rht24</i> were identified from SNP chip-based screening in combination with bulked segregant analysis. The allelic efficacy of <i>Rht24</i> was validated in 242 elite wheat varieties using <i>TaAP2</i> and <i>TaFAR</i> markers. These showed a significant association between genotypes and plant height. <i>Rht24</i> reduced plant height by an average of 6.0-7.9 cm across environments and were significantly associated with an increased TGW of 2.0-3.4 g. The findings indicate that <i>Rht24</i> is a common dwarfing gene in wheat breeding, and <i>TaAP2</i> and <i>TaFAR</i> can be used for marker-assisted selection.