Molecular markers associated with morphological traits in watermelon. HortScience 36

Abstract. Morphological traits were examined in an F3 generation derived from a cross between C. lanatus var. lanatus [(Thunb.) Matsum. & Nakai] and C. lanatus var. citroides. At least three genes, C (yellow) vs. c (red), i (inhibitory to C) vs. I (non-inhibitory to C), and y (yellow) vs. yw (white), with epistatic and inhibitory actions were found to govern the inheritance of fruit flesh color. The high frequency of yellow-fleshed fruit and low frequencies of white and red fruits can be explained by the presence of a new allele (yw recessive to y) in the multiple allele series at the Y locus. The low frequency of tan colored seeds in segregating populations could be explained by at least three genes governing inheritance of seed-coat color. Single factor analysis of variance was con-ducted for each pairwise combination of random amplified polymorphic DNA (RAPD) locus and fruit or seed characteristics. Several RAPD loci were identified to be loosely linked to morphological characteristics. termelon is still in its infancy. Development of a molecular marker linkage map makes it possible to locate and manipulate individual genetic factors associated with complex traits (Jung et al., 1996; Liu, 1997). Defining the genetic control of these traits will assist breed-ers and subsequent molecular mapping will contribute to the development of marker-assisted selection (Perin et al., 1998; Staub et al., 1996). A random amplified polymorphic DNA (RAPD)-based map was developed in a watermelon population segregating for Fusarium wilt resistance (Hawkins et al., 2001). The objectives of this research were to determine linkages among several morpho-logical traits and RAPD markers in the same mapping population and if possible, deter-mine genomic regions controlling watermelon fruit and seed characteristics