Microsatellite markers linked to the locus of the watermelon fruit stripe pattern.

Abstract

Agronomic performance and external and internal appearance of watermelon (Citrullus lanatus) fruit are important traits that should be taken into consideration during the development of a new cultivar, as well as being the principal identification elements used by the consumer, which are based on the external appearance and quality of the fruit. Externally, the fruit can be characterized in terms of the shape, the color of the lower rind, and the presence of grooves and stripes, the stripes can be classified as clearly defined or diffuse. The objective of this study was to identify microsatellite markers linked to the stripe pattern of watermelon fruit to support watermelon improvement programs, with the selection of this characteristic in the plantlet stage. F1 and F2 populations, result of a cross between the cultivars BRS Opara (clearly defined stripes) and Pérola (diffuse stripes), were phenotyped for their fruit stripe pattern. The CTAB 2X protocol was used for DNA extraction and 116 microsatellite markers were examined in a group of F2 plants that had fruit with well-defined stripes and fruit with diffuse stripes. The microsatellite loci MCPI_05 and MCPI_16 exhibited a linkage to the stripe pattern at a distance of 1.5 and 1.8 cM, respectively, with LOD scores of 39.28 and 38.11, respectively, which were located on chromosome six of the watermelon genome. These markers can be used in marker-assisted selection in watermelon improvement programs, by various research institutions.