Genetic analysis and mapping of a striped rind gene (st3) in melon (Cucumis melo L.)

Abstract

As an important commodity trait in melons, the rind is the most direct standard of evaluation for consumers. In this study, we obtained an F2 melon population derived from self-crossing an F1 generation from a cross between X010 (green rind with stripes) and M1-113 (white rind without stripes) and performed genetic analysis and mapping. Genetic analysis revealed that a single dominant gene (st3) controlled the striped rind trait in melons. According to bulked segregant analysis, two DNA bulks were constructed (20 striped and 20 solid-colored rind plants). Next-generation sequencing was used on two parental lines (X010 and M1-113) and two DNA bulks. The st3 gene was identified on chromosome 4 within 2.7 Mbp region. Fourty cleaved amplified polymorphic sequences (CAPS) markers were developed, and sixteen CAPS markers with polymorphisms on chromosome 4 were used for constructing a genetic linkage map, and identifying recombinants in a large F2 population with six new CAPS markers. The location of the st3 gene was narrowed to 172.8 kbp on chromosome 4 between markers M-4-28 (825,401 bp) and M-4-27 (998,261 bp). This study provides a theoretical basis for the fine mapping, cloning and functional characterization of st3.