Genetics of rust resistance in soybean [Glycine max (L.) Merrill]

Abstract

Inheritance of rust resistance in soybean [Glycine max (L.) Merrill] was studied in nine crosses involving 2 susceptible and 5 resistant genotypes. The crosses were made in three triangles keeping one parent common in all the 3 triangles. Seeds of all the generations viz., Pl , P2; Fl , F2 and F3 were divided into two sets, one of which was used in field screening and other for controlled condition study in greenhouse. Results obtained from both the environments are similar. The F2 segregation analysis in all the six susceptible x resistant cross combinations revealed that rust resistance is governed by a single dominant gene. In Bragg x MACS 13, a cross of both susceptible parents revealed that, there is no complementation. In one of the 2 resistant x resistant cross combinations TS 98-21 x EC 389160, there are two different genes imparting resistance. Whereas in the cross, PK 1029 x EC 389165, there was no segregation for rust reaction in any of the generations which reveals presence of the same gene for resistance in both the parental lines. In all these crosses the F2 results were confirmed by studying the F3 progenies.