Characterization of a major QTL for tiller number at the seedling stage in wheat landrace Yanda 1817

Abstract

Abstract Effective tillers contribute to yield through adjusting population structure and affect 1000-kernel weight and kernel number per spike, which are 3favorable for wheat (Triticum aestivum) improvement. Wheat landraces show strong tillering ability and thus considerable potential for utilization in breeding. In this study, tiller number under nutrient solution condition was evaluated for 269 wheat recombinant inbred lines and their parents: the modern cultivar Beinong 6 and the landrace Yanda 1817, which exhibit strong tillering ability. A major QTL, qTN-7B.1, significant in three independent experiments, was detected by linkage analysis and confirmed by sequenced-based bulked segregant analysis. Its positive allele was from Yanda 1817. Pathway enrichment among tiller-bud transcriptome data for the two parents suggested that tillering ability was associated with lignin biosynthesis and energy metabolism. Further combination of differentially gene expression analysis and variant calling identified 33 nonsynonymous SNVs on 20 DGEs. Three differentially expressed genes were identified in the qTN-7B.1region. In particular, TraesCS7B02G282100 encoded cinnamyl alcohol dehydrogenase crucially in lignin biosynthesis was considered candidate gene. Then four genetic markers were developed and the peak of qTN-7B.1 was narrowed between KASP513 and KASP516, and explained 11.04%–19.01% of the phenotypic variation and positively affected kernel number per spike but negatively affected 1000-kernel weight. An allelic frequency test of a natural population revealed that Hap2 (the Yanda 1817 haplotype) and a third haplotype (Hap3) were selected during wheat improvement. This study lays a foundation for map-based cloning of qTN-7B.1 and developed genetic markers showed potentially application in improving plant architecture though marker assistant selection.