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This article in CS

  1. Vol. 43 No. 2, p. 483-488
    Received: Mar 28, 2001

    * Corresponding author(s): cjb2v@virginia.edu
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Genetics of Suicidal Germination of Striga hermonthica (Del.) Benth by Cotton

  1. C. J. Botanga *a,
  2. S. O. Alabib,
  3. C. A. Echekwub and
  4. S. T. O. Lagokec
  1. a Dep. of Biology, Gilmer Hall, Univ. of Virginia, Charlottesville, VA 22903
    b Dep. of Plant Science, Ahmadu Bello Univ., Zaria, Nigeria
    c Univ. of Agriculture, Abeokuta, Nigeria


The germination of giant witchweed [Striga hermonthica (Del.) Benth], a noxious root parasite of many cereal crops, is stimulated by exudates from the roots of both host and non-host trap plants. Forty genotypes of cotton (Gossypium hirsutum L. and G. barbadense L.), a trap crop, were screened in the laboratory, using the cut-root technique, to investigate the variability among these genotypes for their ability to stimulate suicidal germination of S. hermonthica and to determine the inheritance of the trait. The genotypes exhibited significant differences for the trait. S. hermonthica seed germination percentages ranged from 13.3 to 50.0% for the cotton genotypes compared with 47.3% for the susceptible sorghum [Sorghum bicolor L. Moench)] cultivar CK60B. Three cotton genotypes were selected based on their S. hermonthica seed germination stimulation and used as parents in crosses of the combination low × high S. hermonthica seed germination stimulation. The F1s, F2s, and parents of the crosses, RASA(78)11b × ‘SAMCOT-10’ and RASA(78)11b x TX-CABS-1-83 were evaluated in separate experiments in batches of 12 entries. Broadsense heritability estimates for the trait ranged from 71.8 to 78.5%. This was reflected in the discrete frequency distribution of the F2 populations into two classes of high and low S. hermonthica seed germination stimulation, fitting a classical 3:1 phenotypic ratio. These results suggest that S. hermonthica seed germination stimulation by cotton is a qualitatively inherited trait, and that the gene controlling this trait is monogenic and simply inherited, with high S. hermonthica seed germination stimulation dominant over low S. hermonthica seed germination stimulation. It should be possible to select and breed cotton genotypes that produce highly active germination stimulants in large amounts, while maintaining or improving other agronomic attributes.

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Copyright © 2003. Crop Science Society of AmericaPublished in Crop Sci.43:483–488.