Pea Rust in Western Siberia: Resistant Varieties and Defense Mechanisms.

Rust, caused by the fungus Uromyces pisi, is the most harmful disease of peas in temperate regions. It is necessary to search for sources of resistance with different defense mechanisms in the pea gene pool. A set of 38 Pisum sativum accessions of various origin was studied in Western Siberia in 2021-2024. The aim of the research was to assess the accessions in the field and under controlled conditions using seedlings and adult plants, as well as to study the interaction of U. pisi with resistant varieties, and to determine genetic control of rust resistance. All accessions showed partial (incomplete) resistance to rust in the field. A set of 10 resistant varieties was used for studying U. pisi interaction with peas using cytological methods. The protective mechanisms of Russian varieties led to the inhibition of 50-90% spores on leaf surfaces before penetration into the stomata, and a part of the small colonies died without hypersensitive reaction in the tissues. Hydrogen peroxide and phenolic compounds with red and green autofluorescence appeared by the stage of sporogenesis. Five varieties showed adult resistance to rust. A hybridological analysis revealed monogenic dominant control of resistance in two varieties, and digenic control in two others. The information obtained expands the understanding of the partners' interaction in the pathosystem 'U. pisi-P. sativum', and can also be used for breeding pea varieties with different resistance mechanisms.