Identification and validation of genetic loci for tiller angle in bread wheat

摘要

Key message Two major QTL for tiller angle were identified on chromosomes 1AL and 5DL, andTaTAC-D1 might be the candidate gene forQTA.caas-5DL. An ideal plant architecture is important for achieving high grain yield in crops. Tiller angle (TA) is an important factor influencing yield. In the present study, 266 recombinant inbred lines (RILs) derived from a cross between Zhongmai 871 (ZM871) and its sister line Zhongmai 895 (ZM895) was used to map TA by extreme pool-genotyping and inclusive composite interval mapping (ICIM). Two quantitative trait loci (QTL) on chromosomes 1AL and 5DL were identified with reduced tiller angle alleles contributed by ZM895.QTA.caas-1ALwas detected in six environments, explaining 5.4-11.2% of the phenotypic variances. The major stable QTL,QTA.caas-5DL, was identified in all eight environments, accounting for 13.8-24.8% of the phenotypic variances. The two QTL were further validated using BC(1)F(4)populations derived from backcrosses ZM871/ZM895//ZM871 (121 lines) and ZM871/ZM895//ZM895 (175 lines). GeneTraesCS5D02G322600, located in the 5DL QTL and designatedTaTAC-D1, had a SNP in the third exon with 'A' and 'G' in ZM871 and ZM895, respectively, resulting in aThr169Alaamino acid change. A KASP marker based on this SNP was validated in two sets of germplasm, providing further evidence for the significant effects ofTaTAC-D1on TA. Thus extreme pool-genotyping can be employed to detect QTL for plant architecture traits and KASP markers tightly linked with the QTL can be used in wheat breeding programs targeting improved plant architecture.