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Inheritance and Allelism Analysis of Hypernodulating Genes in the NOD3-7 and NOD2-4 Soybean Mutants


This article in CS

  1. Vol. 40 No. 3, p. 700-703
    Received: Sept 19, 1999

    * Corresponding author(s): j-harper@uiuc.edu
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  1. T.D. Vuonga and
  2. J.E. Harper *b
  1. a Dep. of Crop Sciences, Univ. of Illinois, Urbana, IL 61801 USA
    b Soybean/Maize Germplasm, Pathology and Genetics Unit, USDA-ARS and Dep. of Crop Sciences, Univ. of Illinois, 1201 W. Gregory Dr., Urbana, IL 61801 USA


Hypernodulating soybean [Glycine max (L.) Merr.] mutants derived from cv. Williams showed greater early-season dinitrogen fixation potential and partial tolerance to high levels of NO 3 Understanding genetic control is essential to manipulation of this trait. Genetic analysis of the NOD1-3 and NOD4 mutants, and the En6500 mutant, had previously shown that these three mutants were controlled by the same recessive allele at the rj7 locus. However, genetic control of two additional hypernodulating mutants, NOD3-7 and NOD2-4, remained to be verified. We investigated the inheritance and allelic relationship of these latter mutations in relation to those previously studied. The cultivar Harosoy 63 was crossed to the NOD3-7 and NOD2-4 mutants to produce F1 hybrids, F2 progeny, and F2-derived families. Phenotypic segregation was examined. For allelism tests, hypernodulating progeny exhibiting purple hypocotyl, which were isolated from the F2 segregants of the crosses with Harosoy 63, were used for crossing with the NOD2-4 mutant. Resulting phenotypes were visually evaluated for hypernodulation at 14 d after planting (DAP) in the greenhouse. The results of genetic analysis indicated that a recessive allele was responsible for hypernodulation in the NOD3-7 and NOD2-4 mutants. Allelism analysis revealed that although the hypernodulating mutants were isolated from independent mutational events, the rj7 locus controlled NOD-type hypernodulating mutants and the En6500 mutant.

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