Origin and Utilization of Rust Resistance in Groundnut

Abstract

The groundnut (Arachis hypogaea L.) — groundnut rust (Puccinia arachidis Speg.) pathosystem appears to have coevolved in Peru, South America, where the host is known to have been cultivated for almost 4000 years. The groundnut spreaded to the rest of the world after the Spanish and Portuguese colonization of South America. Prior to 1969 the pathogen which was largely confined to South America, but it got firmly established in all the groundnut growing countries in a short span of time (a ‘re-encounter’ phenomenon). The pathogen is highly host-specific and is known by its uredinial stage. Rust is an economically important disease on groundnut, often causing more than 50% yield losses in most groundnut growing areas. Rust resistant genotypes have been identified. The resistance is of a quantitative nature and its inheritance does not seem to be simple. Rust resistance in most genotypes is stable over a wide range of geographic locations except in a few locations, indicating possible variation in the pathogen, which needs confirmation. Rust resistance in groundnut fits neither typical race-specific nor race-non-specific patterns and appears to be an intermediate type falling in the continuum of these two extreme types.