Independent Assortment of Red Stem and Yellow Green in Muskmelon

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Cucurbit Genetics Cooperative Report 6:47 (article 23) 1983

J. D. McCreight
U. S. Department of Agriculture, Agricultural Research Service, P. O. Box 5098, Salinas, CA 93915

Five F2 and 15 repulsion phase backcross (BC) families were scored for red stem (2) and yellow green (3) seedling marker genes. Pooled segregation data indicate independent assortment between these two loci (Table 1).

Table 1. Segregation data for red stem and yellow green.
Phenotype
Normal Yellow green Single Factor X2 Linkage X2
Generation Normal Red stem Normal Red stem    r    yg
F2 272 69 89 30 0.1855 2.9861 4.2705
BC 946 883 1042 940 6.1424 7.1437 13.6853

F2 segregations (by family and pooled) were good fits to the expected 3:1 single factor and 9:3:3:1 dihybrid ratios. BC segregations (by family and pooled) were, however, poorly fitted to the expected 1:1 single factor and 1:1:1:1 dihybrid ratios. BC, contingency table (1), linkage X2 =0.2760 which confirmed the F2 data. Thus, these two loci are not linked.

Literature Cited

  1. Mather, K. 1963. The measurement of linkage in heredity. John Wiley and Sons, Inc., New York. 149 pp.
  2. McCreight, J. D. and G. W. Bohn. 1979. Descriptions, genetics, and independent assortment of red stem and pale in muskmelon (Cucumis melo L.). J. Amer. Soc. Hort. Sci. 104:721–723.
  3. Whitaker, T. W. 1952. Genetic and chlorophyll studies of a yellow-green mutant in muskmelon. Plant Physiol. 27:263–268.