QTL Mapping Of Short Lateral Branch Traits Of Melon(Cucumis Melo L.)

Melon(Cucumis melo L.)is a diploid plant,it is a typical labor-intensive horticultural crop.In the process of melon production,a series of management measures such as hanging vines,forks,and pruning must be carried out on the plants,which consumes a lot of labor and restricts the further development of the melon industry.At present,the improvement of plant type of melon is mainly concentrated ort plant height traits,while the improvement of side branches is very lagging.However,the side branches of melon are very developed,and their development is accompanied by the whole growth cycle of melon.In order to improve the ventilation and light transmission conditions of plants,and the rational distribution of nutrients,it is usually necessary to remove them manually.Due to the lack of ideal plant type,mechanization,light simplification and labor-saving cultivation management are difficult to implement,which indicates the direction of the breeding workers is also a new challenge before them.In this study,a short collateral variation material of the melon melon germplasm PI351131 was named(D581).After several generations of self－purification and purification,the traits were stable,and the QTL locus of short-branched traits of melon was studied with this material.The F2 and F2:3 populations were constructed with the short side branch material D581 and the long side branch H465 as parents.The QTL locus mining of the collateral related traits of melon was carried out by the construction of genetic linkage map.The main results are as follows:1.Genetic analysis of collateral traits in melon.Through phenotypic analysis of the test materials for population,it was found that D581 and H465 showed significant differences in the length of the lateral branches,and the short lateral branches tend to be recessively inherited.F2 population phenotypic data were continuously distributed and super-parent phenomenon,and the frequency histogram tends to be normally distributed,indicating that the melon collateral trait is a typical quantitative trait.2.Construction of Melon Map.Polymorphism of 1136 pairs of SSR primers and newly synthesized 132 pairs of InDeL primers was performed by two parents.193 pairs of SSR markers and 60 pairs of InDeL markers were obtained and used for genotyping.94 pairs were obtained by JionMap4.0 software.The F2 single genotype was constructed to obtain a genetic map containing 12 linkage groups covering the full length of 1433.3cM.There were 253 markers on the map,including 193 pairs of SSR markers and 60 pairs of InDeL markers.The spacing is 5.67cM,the length of each linkage group is 77.8-197.0cM,the number of markers in each linkage group is 14-32,and the average genetic distance between each linkage group marker is 3.41-10.94cM,which is marked by the genetic distance and physical distance.Linear analysis indicated that the map is suitable for QTL mapping.3.QTL mapping of collateral traits in melon.Using QTL IciMapping V4.1 software,the QTL locus of collateral-related traits was mined by complete interval mapping(ICIM).In the two seasons,31 QTL loci were obtained and distributed on the 7th,8th and 12th linkage groups and it is more than 4 QTL sites.In the two seasons,three QTL loci were located in the total length of the lateral branches,with a cumulative contribution rate of 23.90%;four QTL loci were located in the lateral branch length,the cumulative contribution rate was 40.48%;and the total length of 11-15 sections was located in two QTLs.The cumulative contribution rate was 33.27%;the total length of 16-20 sections located 7 QTL loci,the cumulative contribution rate was 65.27%;the total length of 21-25 sections located 7 QTL loci,the cumulative contribution rate was 74.12%,The total length of 26-30 sections is 3 QTLs,the cumulative contribution rate is 32.99%;the total length of 11-20 sections is 2 QTLs,the cumulative contribution rate is 30.00%;the total length of 21-30 sections is 3 QTLs,the cumulative contribution rate It is 37.45%.The QTL loci of the total length of the lateral branches and the length of the lateral branches were often at the same locus,and the total length of the lateral branches and the length of the lateral branches were detected in the spring and autumn.QTLs were detected in the SSR029716-ECM88 marker in the 8th linkage group.A total of 7 QTL loci were detected in the marker interval,and the cumulative contribution rate was 75.66%.This interval is a focus of future research.