干旱条件下小麦粒长QTL定位与分子标记开发OA

Drought stress during the grain filling period severely impacts grain development in common wheat.Grain traits such as grain length and grain width are closely associated with yield.However,genetic dissection of these traits under drought stress is significantly insufficient.In this study,a BC3F4 backcross introgression line population derived from drought-tolerant cultivar Jinmai 47 and drought-sensitive cultivar Yumai 13 was employed to identify important genetic loci controlling grain length under drought stress via BSA-seq analysis.A QTL significantly associated with grain length under drought stress was detected on chromosome 1D within the 432.65-460.02 Mb interval and was designated GLd1.The GLd1 was consistently detected in three additional backcross introgression line populations.Molecular markers were developed based on sequence polymorphisms between Jinmai 47 and Yumai 13 within the GLd1 interval,further narrowing the can-didate interval to 1.01 Mb.Using the KASP marker 1D-SNP57 developed within the GLd1 interval,genotype-phenotype association analysis was conducted in a natural wheat population consisting of 325 accessions.Genotypes carrying the Jinmai 47 allele exhibited significantly longer grains than those carrying the Yumai 13 allele,confirming the close associa-tion of this marker with grain length under drought stress.This study identifies a novel QTL for grain length under drought stress in wheat and provides a KASP marker applicable for grain length selection,offering new genetic resources and prac-tical tools for breeding drought-tolerant and yield-stable wheat varieties.