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Cyst Nematode vs. Tolerant and Intolerant Soybean Cultivars
Author(s) -
Radcliffe D. E.,
Hussey R. S.,
McClendon R. W.
Publication year - 1990
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1990.00021962008200050001x
Subject(s) - soybean cyst nematode , cultivar , heterodera , biology , shoot , agronomy , nematode , nematology , horticulture , ecology
The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is a major pathogen in soybean [ Glycine max (L.) Merr.], and although resistant cultivars have been developed, new races of H . glycines build up that are capable of damaging the resistant cultivars. The use of tolerant and susceptible genotypes of soybean, which support SCN development and reproduction without serious plant growth reduction, is a promising method for limiting SCN yield suppression without creating selection pressure for new races of this nematode A field study was conducted for 2 yr to determine the effect of SCN initial population ( P i ) densities on soybean root and shoot development in the intolerant and susceptible cultivar, Bragg, and the moderately tolerant cultivar, Wright. Shoot and root growth was stimulated at the low P i but reduced at high P i in both years. Harvest seed weight showed a similar response in 1986, but declined steadily with increasing P i in 1987 when there was less rainfall. The moderately tolerant cultivar, Wright appeared to be a smaller, more efficient plant than the intolerant cultivar, Bragg. Wright had a smaller root system than Bragg, but the roots in the top 0.15 m exhibited compensatory growth in response to early infection by SCN whereas Bragg root growth was suppressed. Wright also had a proportionately deeper root system, compared to Bragg, and this may be part of the mechanism of tolerance.