Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] flesh color is
controlled by several genes to produce red, orange, salmon yellow, ca
nary yellow, or white. The objective of these experiments was to study
the interaction of three independently reported gene loci, each havin
g two or three alleles: C (canary yellow) versus c (red), y (salmon ye
llow) versus Y (red) versus y degrees (orange), and i (inhibitory to C
) versus I(noninhibitory to C). The interaction of C, y, y degrees and
i is of interest to those developing new cultivars of watermelon and
has not been reported previously. Five crosses were used to study gene
action: Yellow Baby x Tendersweet Orange Flesh, Yellow Doll x Tenders
weet Orange Flesh, Yellow Baby x Golden Honey, Yellow Doll x Golden Ho
ney, and Yellow Baby x Sweet Princess. Based on performance of P-A, P-
B, F-1, F-2, BC1A, and BC1B, the parents have the following genotypes:
Yellow Baby = CCYYII, Yellow Doll = CCYYII, Tendersweet Orange Flesh
= ccy degrees y degrees II, Golden Honey = ccyyII, and Sweet Princess
= ccYYii. Segregation of flesh color in the progeny of the five famili
es supported the previous report of a multiple allelic series at the y
locus, where Y (red) was dominant to y degrees (orange) and y (salmon
yellow). In conclusion, epistasis is involved in the genes for major
flesh colors in watermelon, with ii inhibitory to CC (canary yellow),
resulting in red flesh, and CC (in the absence of ii) epistatic to YY,
producing canary flesh.