QTL Mapping For Stalk Related Traits In Wheat

Wheat is an important grain crop in China.The introduction of the dwarf gene in the green revolution and improvement of the field panting condition have significantly promoted the wheat production.However,lower plant height inevitably result in reduced biomass,when the harvest index reaches a certain level the further improvement of its yield potential largely depends on the increase in biological yield.The key to coordinating this contradictory relationship is to improve the quality of the stalk,strengthening the selection of the quality of the stalk under a certain plant height.In this study,a RIL Population with 190 lines,derived from the cross of Xinong1376/Xiaoyan81,was analyzed by wheat 90 k SNP genotyping chips technology.Subsequently,a high density genetic map was constructed.QTL for stalk-related traits were analyzed using IciMapping v4.1 by ICIM model.The main findings are as follows.1.After linkage analysis,a genetic map of wheat consisting of 43 linkage groups was constructed with 5944 polymorphism SNP markers,located in21 chromosomes of the wheat genome,covering 2955.17 cM with an average interval distance of 0.5cM.The distribution of markers between wheat chromosomes was uneven,2847 SNP makers were from A genome,with 47.9% of total number,covering 1448.03 cM,with an average interval distance of0.51 cM,2617 SNP markers were from B genome,with 44% of total number,covering1091.88 cM,with an average interval distance of 0.42 cM,D chromosome group contains the smallest number of markers,only 461,accounting for 7.7% of the total number,covering404.78 cM,with an average interval distance of 0.88 cM.2.With the constructed genetic map,QTL was carried out by using mapping software QTL IciMapping v4.1 for stalk related trait in four cultivation environments.A total of 121 QTLs were detected in the 18 chromosomes except for1D?4A?7D,including 20 major effect QTL,a single QTL can explain 2.61%-13.34% phenotypic variation.3.A total of 89 QTLs related to plant height,ear length and the internode length were detected in 1A,2A,2B,2D,3A,3B,3D,4B,5A,5B,5D,6A,6B,6D,7B chromosomes,of which the major effect QTL has 19.The phenotypic variation of single QTL explained was3.14%-13.34%,40 QTL additive effect from Xinong 1376,49 from small Xiaoyan 81.4.The QTL for the basal stem diameter,culm wall thickness and pith diameter weredetected on the 1B,2A,2D,3A,4B,5A,6A chromosomes,A major effect QTL locus was found on the 4B chromosome which could control the first basal stem diameter and pith diameter,explained 10.17% and 6.8% phenotypic variation respectively.In addition,a polymorphic QTL locus was found on the 6A chromosome,which could affect the first and second basal pith diameters.5.16 QTL were detected for the external mechanical properties?stem hardness ? stem gumminess? stem chewiness ?stem resilience?,which located on the chromosome 3B,4B,5B,6D,and 7A,respectively.The 4B and 5B chromosomes had the most QTL for the external mechanical properties,and the QTL loci of different traits clustered in a certain chromosomal hot spot.A major stable expression effect QTL controlling the stem chewiness was detected between the markers Excalibur_c5120₉38 and BobWhite_c26082₂39 on the5 B chromosome,and it could be detected under different environments.