![Sample our Environment & Agriculture journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5934/TOC-Subject-Sample-2021-Environment-Agriculture.jpg"})
Abstract
To obtain soybean (Glycine max. L. Merr.) lines harboring the Rj 2- and Rj 4-genes, the Rj 2-cultivar IAC-2 (Genotype Rj 2 Rj 2 rj 4 rj 4) and Rj 4-cultivar Hill (rj 2 rj 2 Rj 4 Rj 4) were crossed. Genotype Rj 2 Rj 2 Rj 4 Rj 4 was selected based on its nodulation reactions with the combined inoculum of Brady rhizobium japonicum strains Is-1 (nodulation-type B; nodulates the Rj 4-cultivar but does not nodulate the Rj 2-cultivar) and Is-34 (type C; nodulates the Rj 2 Rj 3-cultivar but does not nodulate Rj 4-one). In the F1 and F2 generations, both Rj-genes segregated according to Mendel's laws. The genotype of the F2 plant could be considered to be Rj 2 Rj 2 Rj 4 Rj 4, if all the tested progenies from the F2 plant nodulated ineffectively with the combined inoculum. Ten progenies from each of eight F2 plants were assayed for the Rj-phenotypes and four promising F2-plants were isolated. The progenies (F3 generation) from the selected lines were transplanted in the field, and the F4 progenies were examined for their compatibility with the combined inoculum strains. Three promising lines homozygous for both Rj 2- and Rj 4-genes and one line homozygous for Rj 2 and heterozygous for Rj 4 were isolated. The progenies (F5 generation) from the selected lines were examined for their compatibility with the combined inoculum strains, and it was eventually concluded that 12 lines (F4 generation) were characterized by the genotype Rj 2 Rj 2 Rj 4 Rj 4.