Genetic Analysis And Quantitative Trait Locus(QTL) Mapping Of Mung Bean Growth Period Related Traits

Mung bean is the important edible bean crop.The study of mung bean growth period genes not only helps to understand the law of mung bean growth period changes,but also helps to cultivate new varieties with different maturity.In this study,the RIL population consisting of 261 individuals,constructed from "VC2917×Budgerigar Green" was used.From 2017 to 2019,a total of 5 habitats were planted on the farm of Nanyang Normal University.On the basis of investigating the six basic growth period traits of emergence date,clover date,branch date,flower initiation date,flowering date,and maturity date under each habitat condition,the six basic fertility conditions under each habitat condition were firstly calculated.And analyzed its genetic laws,and then selected a habitat with good trait segregation,complete data and genetic stability in 2018 and 2019,and finally calculated the interval of 15 growth periods under these two conditions.Duration,and preliminary analysis and analysis of two-site interaction effects on 21 growth-related traits in these two habitats.The main results are:1.Genetic analysis of six important growth stages of mung bean seedling stage,three-leaf stage,branching stage,initial flowering stage,flowering stage and maturity stage showed that the genes of six growth stages of mung bean were well separated.Four growth stages were normally distributed apart from the seedling and three-leaf stage.The main peak were checked in the 6 traits normally distribution curves,imply the inheritance of traits was mainly controlled by the major gene QTL.The heritabilities of emergence stage,three-leaf stage,branching stage,initial flowering stage,flowering stage and maturity stage are 0.510,0536,0.490,0.650,0.955 and 0.954.2.QTL loci were detected in 21 growth traits analyzed in this study,and a total of 52 QTL loci with LOD>2.0.A total of 31 QTL loci were detected in 2018,and 21 QTL loci were detected in 2019.In general,the QTLs associated with growth-related traits are mainly distributed on the 2 and 11 genetic contribution rate of a single locus ranged from3.3% to 15.93%.3.The QTL loci with LOD ﹥ 2.5 of six important growth stages are follows: oneseedling stage QTL locus was detectedin each of 2018 and 2019 year,which were located inthe marker mus118 to mus35 on chromosome 6,the LOD values are 3.97 and 4.02.One QTL locus was detected in each of the three-leaf stage in 2018 and 2019,both located in the marker MUS168 to Mchr7-23 on chromosome 6,with LOD values of 4.10 and 5.43.A QTL locus was detected in each of 2018 and 2019,located between the Mchr10-9 to Mchr5-37 and Mchr10-49 to HAAS_VR₁519 markers on chromosomes 9 and 11,with LOD values of 5.59 and 6.28.Two initial flowering sites were detected in 2018 and one was detected in 2019,the three QTL sites were located on Mchr2-9 to MUS540,MUS869 to MUS171 and MUS171 to on chromosomes 1,2 and 2.LOD values were3.39,6.07 and5.13.Between the MUS617 markers,the LOD values were 3.39,6.07,and 5.13,in the phase,Two and one loci of flowering stage were detected in 2017 and 2019,The three QTL locis were located on chromosomes 2,11,and 11.The LOD values were 4.50,4.93,and 4.99 between Mchr11-50 and CEDG198,Mchr10-1 to Mchr10-5,and HAAS_VR₁519 to HAAS_VR₁270.One maturity stage QTL locus was detected in each of 2018 and 2019 year,which are located between Mchr10-1 to Mchr10-5 and HAAS_VR₁519 to HAAS_VR₁270 on chromosome 11.The LOD values were 4.99 and3.75.4.The results of the two-point interaction analysis of 21 growth traits showed that the significant interactions in 2018 and 2019 were 42 and 47 pairs.The single contribution rate of loci to traits ranged from 22.94% to 85.79%,and most of the loci were interactions between non-linked markers and non-linked markers.5.Regression analysis between the six growth period traits and mung bean yield showed that the seedling stage and maturity stage were positive regression with yeid,the other four growth periods were negative regression with yield.The relative importance of each growth period trait to the yield is: flowering stage（R=-0.100**）> branching stage（R=-0.122*）> three-leaf stage（R=-0.100）> maturity stage（R=0.029）> initial flowering period（R=-0.024）> seedling stage（R=0.017）.