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Linkage of loci controlling nodulation (N(1)) and testa variegation (V) was studied for cultivated peanut (Arachis hypogaea L.). The lines M4-2 (nonnodulating, variegated; VVn(1)n(1)n(2)n(2)N(3)N(3)) and UF 487A (nodulating, nonvariegated; vvN(1)N(1)n(2)n(2)N(3)N(3)) were used as parents in the crosses M4-2 x UF 487A, M4-2 x (UF 487A x M4-2), and their reciprocals. Individual plants were evaluated for nodulation and testa variegation in the F(1), F(2), F(3), F(1)BC(1), and F(2)BC(1) generations. Data indicate that the N(1) and V loci are linked with calculated crossover percentage of 7.1%.

A nonnodulating line (M4-2) and three normal nodulating lines (UF 487A, PI 262090, and Florunner) of peanut (Arachis hypogaea L.) were crossed in full diallel to investigate the inheritance of nodulation. Data from F1, F2, F3, F1BC1, and F2BC1 generations indicated that three genes control nodulation at three independent loci, with nodulation being a product of two genes and inhibited by a third gene when it is dominant and the others are homozygous recessive. A genetic model has been proposed that describes the nonnodulated genotypes as n1n1n2n2N3N3 or n1n1n2n2N3n3 and all other genotypes as normally nodulated except n1n1N2n2N3-, which has reduced nodulation when the n1n2N3 male gamete unites with the n1N2- female gamete or when the n1n2n3 male gamete unites with the n1N2N3 female gamete.