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Genetic Allelism of Nodulation Response Genes Rj 1, Rj 2, and Rj 4 in Soybean
Author(s) -
Devine T. E.,
O'Neill J. J.
Publication year - 1989
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1989.0011183x002900060003x
Subject(s) - biology , allele , locus (genetics) , genetics , genotype , gene
Several qualitatively inherited genes ( Rj 1, Rj 2, and Rj 4) controlling nodulation response have been reported in soybean, Glycine max (L.) Merr. This study was undertaken to determine whether these alleles were located at distinct genetic loci, or whether one or more were located at the same locus. The F 3 progeny from crosses of genetic stocks of each allele were evaluated for nodulation response. The responses due to the Rj l allele were evaluated in the field. The responses due to the Rj 2 allele and the Rj 4 allele were evaluated in sterile vermiculite in growth trays following controlled inoculation with bradyrhizobial strain USDA 7 or USDA 61, respectively. The F 3 seed lots were subdivided to permit assay for more than one allele. Genotypes of F 2 plants were rationalized from F 3 progeny. Allelism tests established that the Rj l, Rf l and Rj 4 alleles were distinct in their segregation and must be located at three distinct genetic loci. The Rj l gene has been located 40 ± 2 centimorgans from the F gene. Both Rj 2 and Rj 4 were found to segregate independently of the F locus, confirming that they are not at the Rj l locus. Therefore, soybean breeders have the option of constructing soybean genotypes containing all or any combination of these alleles if desired.