Inheritance of Enzymatic Activities Related to Asian Rust Resistance in Soybean [Glycine max (L.) Merrill]

Only limited information is available on biochemical response of soybean genotypes differing in their pathogenesis response to Phakopsora pachyrhizi infection. Hence, this study was undertaken to investigate enzymes, viz., chitinase, peroxidase, and polyphenol oxidase that contribute towards improving soybean rust resistance. Contribution of these three enzymes towards rust resistance in soybean was investigated at pre-(45 days after sowing) and post-infection (75 days after sowing) stages. Inheritance of their activities was studied in crosses between a resistant (EC 241780) and two susceptible parents (Kalitur and NRC 7). Rust resistance was found to be associated with increased activities of all three enzymes investigated in the resistant parent, F-1 crosses and backcrosses with resistant parent. Resistant parents/generations showed higher enzymatic activities than susceptible one at the post-infection stage. Among the three enzymes studied, chitinase activities were found to be mostly associated with rust resistance in soybean. Complementary gene interaction was found to be associated with expression of the enzymes investigated during soybean rust resistance. Higher chitinase activities at the post-infection stage could be the best criteria for rust-resistant plant selection in parents, F1s, and segregating generations.