Genetic Analysis And Gene Mapping Of Watermelon Resistance To Cucumber Green Mottle Mosaic Virus

Watermelon(Citrullus lanatus)belongs to Cucurbitaceae,as an important economic crop,is one of the top ten fruit crops.With the adjustment and improvement of agricultural structure,the planting area of watermelon in China has ranked the first in the world.Cucumber green mottle mosaic virus disease is a main disease affecting watermelon production,which is transmitted through seeds.Watermelon seedlings infected by CGMMV display some typical disease symptoms,such as mosaic patterns,abnormal leaves,stunting,abnormal fruit,necrosis,reduction in yield anddecline in quality.In this study,a wild type watermelon with resistance to CGMMV,'PI595203',and a cultivar with high susceptibility to CGMMV,'M1511-3',were used as parent lines to construct Fi and F2 population by hybridization and self-cross to analyse the inheritance of resistance to CGMMV.The resistant genes for CGMMV were preliminarily mapped by BSA method based on the whole genome sequencing.The main results were shown as follows:1)Resistance identification of 'PI595203' and 'M1511-3'.'PI595203'and 'M1511-3' were inoculated with CGMMV,and then symptoms investigation,CGMMV gene ex:pression analysis and ELISA test were performed.We found that 'PI595203',was resistant.to CGMMV,while 'M1511-3' was highly sensitive to CGMMV.2)Genetic analysis of CGMMV-resistance gene.The F2 population was deduced from the cross of the CGMMV resistance line'PI595203'and susceptible line' M1511-3'.F1(30 individuals)and F2(30 individuals)were inoculated with CGMMV,respectively.We found that F1 progenies were susceptible.The traits were separated in hybrids F2 generation and showed Gaussian distribution,indicating that CGMMV-resistance phenotype is controlled by mulhi-recessive genes in watermelon.3)CGMMV-resistance gene mappingResistant individuals and susceptible individuals in the F2 population were selected for geneome-sequencing.One candidate region related to disease resistance traits was obtained,with the total interval of 1.01 Mb.Association analysis of genome sequences and resistance phenotype provide us 56 candidate genes.