QTL Analysis Of Fruits Related Traits In Melon(Cucumis Melo L.)

Muskmelon?Cucumis Melo L.?is an annual herb of the genus Cucurbitaceae.It is a horticultural crop widely grown worldwide and is a fruit that is popular among consumers.In recent years,with the improvement of people's living standards,consumers' requirements for the quality and variety of melon fruit have gradually increased.Therefore,improving the inner and external quality of melon and selecting and breeding more abundant melon varieties are the current melon breeding's important work content.In this experiment,F₂ populations were obtained from snake melon M4-75 and Mapao melon X207 as parents,and based on parental genome re-sequencing data the CAPS markers were developed for construction of the genetic linkage map.The QTL analysis of fruits related traits in melon was also carried out.The results are as follows:Fruits related traits in melon,including fruit length,fruit width,fruit shape index,flesh thickness and flesh p H were all quantitative traits.Fruit length,fruit width,fruit shape index and flesh thickness were significantly correlated.Based on parental genome re-sequencing data,700 CAPS markers were designed.180 polymorphic CAPS markers were verified with the DNA of the two parents and F1 generation,and the polymorphic rate was 25.7%.A genomic linkage map of melon was constructed with 165 CAPS markers and the F₂ population containing 93 individuals.The map consisted of 12 linkage groups corresponded to the chromosomes of melon genome.The linkage group 5 contains the largest number of CAPS markers,which was 18.The coverage length of whole genome in melon was 1019.81 cM,and the average distance between two markers was 6.18 cM.The length of the 12 linkage groups ranged from 39.03 cM to 122.65 cM.The linkage group 11 was the smallest,which was 39.03 cM and the linkage group 8 was the largest in the length which was 122.65 cM.A total of 14 QTLs about fruits related traits were detected,and the LOD value ranged from 2.67 to 9.63,which could explain the phenotypic variation rate of 7.60%?35.18%.There were 2 QTLs in fruit length,located on chromosome 4,11 and 2 QTLs in fruit width,located on chromosome 10,11.The 5 QTLs of fruit shape index were located on chromosome 1,2,4,6,11.3 QTLs related with flesh thickness were located on chromosome 5,7,11.There were 2 QTLs associated with flesh p H located on chromosome 3,5.Among them,the QTL Fw11.1 related with fruit width contributed the most,which was 35.18%.It was located between the markers 11-16-E and 11-27-MS of the linkage group 11,and the closest genetic distance from the flanking markers was 0.32 cM.The additive effect was 0.87.