Molecular Detection of the Adult Plant Leaf Rust Resistance GeneLr34in Romanian Winter Wheat Germplasm

Abstract

Wheat continues to be one of the most cultivated cereals in the world, and also in Romania. Leaf rust caused by Puccinia triticina reduces the wheat yield and grains quality worldwide. In the context of climate change, leaf rust has become a more important problem for both wheat growers and breeders in our country. Use of genetic resources, carrying rust resistance genes, play an important role in breeding programs leading to resistant varieties, which can have positive impact on environment and economy. Therefore, the identification of resistance genes in modern wheat cultivars and breeding lines, and then selection of the best resistance genes combination(s) are the first steps for a successful breeding program. At present, one of the best known and studied adult plant leaf rust resistance gene is Lr34 that contributes significantly to durable leaf rust resistance. The functional markers that enable early detection of this gene are a major advantage in the wheat breeding. The aim of this study was to evaluate the presence of the slow rusting resistance gene Lr34 in Romanian wheat germplasm, using cssfr4 and cssfr5 molecular markers. Screening of 47 winter bread wheat cultivars and 47 breeding lines with these markers showed the presence of the Lr34 resistant haplotype in 62% (homozygous genotypes) of the total genotypes. A high frequency (79%) of Lr34 resistance allele was found among 47 breeding lines, suggesting that maintenance of a high frequency of this allele represents a real advantage for the development of adult plant resistance in Romanian breeding programs.