| Melon(Cucumis melo L.)was an annual herb belonged to the Cucurbitaceae family.Melon fruit had a special sweet taste which was also impressed by the consumers.Nowadays,breeding experts focused more on the quality traits of melon and tried to carry out the in-depth research.The new developed markers were used for gene mapping of melon fruit quality traits to find the tightly linked markers.The result could contribute to accelerate the process of melon breeding.In this study,170 BC1P1 individuals were obtained from the cross of muskmelon MR-1 and the thin skin melon M1-15.The SNP-CAPS markers were developed with the genome re-sequencing data based on the parent materials and used to construct the genetic linkage map for the QTL analysis of main fruit traits.Based on the results,the targeted markers were also used for the marker-assisted selection analysis in the melon germplasm resources,which related with the fruit traits.The results were as follows:Based on parental genome re-sequencing data,578 SNP-CAPS markers were designed.240 polymorphic SNP-CAPS markers were verified with the DNA of the two parents and F1 generation,the polymorphic rate was 41.5%.QTLIci Mapping V3.3 software was used for the linkage map construction and QTL analysis with the BC1P1 population containing 170 individuals.A genomic linkage map of melon was constructed with 200 SNP-CAPS markers,it consisted of 12 linkage groups corresponded to 12 chromosomes of melon genome.The coverage whole genome length of melon was 1710.4 c M,and the average distance between two markers was 8.6 c M.The length of the 12 linkage groups ranged from 111.66 c M to 183.53 cM,linkage group 10 was the smallest,which was 111.66 c M and linkage group 2 was the largest both in the length and the average distance which was 183.53 c M and 10.80 c M respectively;the average distance of the linkage group 8 was the smallest,which was 6.63 c M;linkage group 6 contains the largest number of CAPS markers,which was 20 and linkage group 10 contained the least,which was 11.QTLs for the main fruit traits of melon were mapped to 15 QTLs,distributed on the linkage linkage groups 1,2,4,5,6,7,8,9 and 11.Four QTLs associated with fruit length and positive additive effect were distributed in the linkage groups 1,5,6 and 8 with the total contribution rate of 46.82%.One positive additive effect QTL associated with fruit width was detected on chromosome 8 and the value of contribution ratio was 10.56%.Four positive additive effect QTLs associated with the fruit shape index including one major QTL were detected on chromosome 8 with a contribution rate of 38.62%.Fruit length,fruit width,and fruit shape index are linked to the 8th linkage area.The contribution rate of five QTLs associated with the fruit weight were more than 15% and the additive effect was negative.One QTL associated with the brix contents was more than 15% and the additive effect was negative.Five markers related with the main fruit traits were analyzed with 60 melon materials.Marker M4-2 and M11-18 were tested for fruit weight.The coincidence rates of MAS detection and field phenotypic identification were 67% and 30%.MAS testing of fruit shape index was carried out using marker M9-9-1,with the result of 48%.M8-14 and M6-2 were used for fruit width and fruit length,the results of coincidence rates were 62% and 63%. |
PDF Full Text Request