小麦茎秆倒伏性状的QTL定位与候选基因挖掘OA

Lodging is jointly regulated by genetic factors and environmental conditions.Elucidating its genetic basis and mapping key quantitative trait loci(QTLs)hold profound significance for improving stem quality of common wheat(Triticum aestivum L.),thereby ensuring stable wheat yields and advancing genetic improvement programs in breeding practices.In this study,a doubled haploid(DH)population derived from the cross between Zhongke 0101 and Xinmai 23 was used as experimental materials.Combined with a high-density genetic linkage map,QTL mapping for lodging-related traits of the DH population was performed across four environments.Candidate genes associated with major effect QTL clusters were predicted through gene functional annotation and analysis of public gene expression databases,and validated by RT-qPCR.The main results showed that:All lodging-related traits exhibited high heritability and abundant genetic variation within the DH population.Specifically,stem strength-related traits,including thrust and breaking strength of basal internodes,was significantly or extremely significantly positively correlated with the stem diameter and wall thickness of the second and third basal internode.Linkage analysis of the lodging trait was conducted using a high-density genetic linkage map of wheat,and a total of 11 QTL clusters associated with multiple traits were identified,which were distributed on chromosomes 2B,4A,4B,4D,5A,6D,and 7B,respectively.These QTL clusters explained the phenotypic variation ranging from 4.50％to 25.13％.A novel QTL cluster,named as Qcd3/ct3.cas-6D,was mapped to the genomic interval of 25.44-38.81 Mb on chromosome 6D.The candidate QTL cluster was tightly linked to two important lodging-related traits:culm diameter of the third basal internode and culm wall thickness of the third basal internode.This candidate QTL cluster is a stable locus consistently detected across multiple environments,explaining the phenotypic variation ranging from 7.89％to 9.80％for these traits.Within this interval,three potential candidate genes were predicted to be involved in two critical biological pathways related to cell wall fortification:the extracellular matrix signaling pathway associated with pectin activation and modification,and the phenylpropanoid pathway leading to lignin biosynthesis.Over all,these finding,which QTL clusters associated with multiple traits and candidate genes were identified,not only enrich the genetic resources for wheat stem lodging resistance but also provide important theoretical basis for the further excavation of lodging resistance-related genes and the development of molecular breeding strategies.