The flesh color of watermelon (Citrullus lanatus) is an important fruit quality trait that helps to determine fruit attractiveness and is potentially beneficial to human health.Previous inheritance analyses determined that a single dominant gene, Yscr, produces the scarlet red flesh color rather than the coral red flesh color in watermelon.However, no genomic region or gene-based molecular markers for the locus Yscr have been reported thus far.In the present study, two high-density genetic maps and whole-genome variation detection aided by genome resequencing were first map the flesh color locus Yscr to a small region on chromosome 6 based on two independent populations derived from two scarlet red-fleshed lines and Kitchen Accessories two coral red-fleshed lines.Two major quantitative trait loci located in the same genomic regions were identified in the F2 and BC1P2 populations and explained 90.
36% and 75.1% of the phenotypic variation in flesh color, respectively.Based on the genetic variation in the two parental lines, newly developed PCR-based markers narrowed the Yscr region to 40 Kb.Of the five putative genes in this region, four encoded glycine-rich cell wall structural proteins, which implied that a new regulatory mechanism might occur between scarlet red- and coral red-fleshed in watermelon.Moreover, the genotypes of two newly developed InDel markers (InDel27_fc6 and InDel28_fc6) were completely consistent with the phenotypes in the F2 and BC1P2 populations and all 56 scarlet red-fleshed watermelon accessions.
The results presented here provide valuable information for marker-assisted selection of flesh 5 Piece Full Upholstered Bedroom color breeding and the functional validation of candidate genes in watermelon.