Reproductive Advantage Associated with Resistance to Soybean-Cyst Nematode1
- V. D. Luedders and
- L. A. Duclos2
Cultivars of soybeans [Glycine max (L.) Merr.] resistant (R) and susceptible (S) to the soybean-cyst nematode (Heterodera glycines Ichinohe) were grown separately and together on plots heavily infested with tl~e nematodes and on noninfested plots. Two-cultivar (R and S) mixtures in three maturity groups were grown at three densities for 3 years; each cultivar was also grown in pure stand. The mixtures of equal numbers of R and S seeds were made each year. The reproductive advantage of the R cultivar (i.e., the ratio between yield of R cultivar and yield of S cultivar) was always higher in the mixtures than in the pure stands and higher on infested than on noninfested soil. Since the selective advantage of the R cultivars was higher on soybean-cyst nematode infested land, growing segregating populations for several generations on heavily infested land should increase the frequency of R plants. In such populations, segregation would also increase the frequency of R plants when some genes conditioning resistance were recessive, as in race 3 resistance.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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