Male Sterile, ms, in Watermelon not Linked to Delayed Green, dg and I-dg

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Cucurbit Genetics Cooperative Report 16:79 (article 29) 1993

Xingping Zhang and Bill Rhodes
Department of Horticulture, Clemson University, Clemson, SC 29634-0375

The genetic male-sterile ms, from China (1) has been reported to be unlinked to gms (1) and Sp (2). Data are reported here on its relationship to the two genes that determine delayed green – dg and I-dg.

To transfer dg (and its epistatic gene, I-dg) into the male-sterile line, the following cross was made in 1990: ms ms Dg Dg i-dg i-dg and Ms Ms dg dg I-dg I-dg.

The fertile, normal green F1 (Ms ms Dg dg I-dg i-dg) was selfed in the spring of 1991. The F 2 popularion was tested in the greenhouse in the fall of 1991. An F2 populationof 111 individuals was selected first for delayed green and then male sterility. the F2 seedling population consisted of 88 normal: 23 delayed green (13:3 ratio, X2=0.283). The 23 delayed green plants were grown out for fertility testing and seed. Seven (7) male-sterile recombinants were found among the 23 delayed green progeny, consistent with a 61:3 segregation of male sterile, delayed green (X2=0.651).

Finally, the delayed green, male gertile class was obtained by subtracting the 7 delayed green, male sterile from the 23 delayed green total in the population. Thus, there were 16 delayed green, male fertile individuals in the F2, consistent with a 55:9 segregation of delayed green, male sterile (X2 =0.011).

These preliminary data suggest that ms is assorting independently.

Literature Cited

  1. Murdock, B.A., N.H. Ferguson and B.B. Rhodes. 1991. Segregation data suggest male sterility genes gms and ms in watermelon are not in the same linkage group. Cucurbit Genetics Coop. Rpt. 14:90-91.
  2. Murdock, B.A. and N.H. Ferguson. 1992. Segregation data suggest male sterility gene ms and the spotted gene Sp in watermelon are not in the same linkage group. Cucurbit Genetics Coop Rpt. 15:72-73.
  3. Rhodes, B.B. 1986. Genes affecting foliage color in watermelon. J Hered. 77:134-135.
  4. Zhang, Xingping and Ming Wang. 1990. A genetic male-sterile (ms) in watermelon from China. Cucurbit Genetics Coop. Rpt. 13:45-46.