Principal approaches and achievements in studying race composition of wheat stem rust

Abstract

Wheat stem rust caused by the biotrophic fungus Puccinia graminis f. sp. tritici is a dangerous disease that seriously damages the economics in many countries of the world. The review contains information about epidemics of wheat stem rust and causes of their emergence worldwide. Recently wheat stem rust epidemics have been recorded in the northern regions of Kazakhstan and on the territories adjacent to Omsk Region of Russia. It has been shown that severe wheat stem rust epidemics occur mainly due to the emergence of new virulent races of the disease agent and to growing susceptible wheat cultivars. New methods of studying the race composition of the fungus are described as well as the use of the previous and current differential sets for race determination of P. graminis f. sp. tritici. The results of developing molecular markers and assessing their effectiveness in studying stem rust races are presented. Wheat stem rust races dominant in major grain-growing countries of the globe and their typical peculiarities are described. The paper contains information on identifcation of race Ug99 and of its variations including data on areas of their dissemination and on their virulence to Sr-resistance genes. The existence and emergence of other races of the agent potentially dangerous for commercially important genes for stem rust resistance is also described. Currently in nature strongly virulent races of P. graminis f. sp. tritici are circulating with wide geographical coverage and their virulence is absolutely different from the virulence of race Ug99. Historical and modern data on studying the race composition of the pathogen in Kazakhstan are summarized. It is stated that the use of the old standard differential set and an incomplete North American system of race nomenclature in experiments prevents measuring similarity between Kazakhstani races and the worldwide known races of the pathogen. It has been shown that there is a need to continue studies on the intraspecies structure of the disease agent’s population in Kazakhstan with the use of the modern differential set, on determination of race composition and ways of emergence of new races potentially dangerous for commercial wheat varieties.

Genome-wide association mapping for resistance to leaf, stem, and yellow rusts of common wheat under field conditions of South Kazakhstan

“…The population of P. graminis f. sp. tritici in Kazakhstan is represented by six pathotypes: TFK/R, TDT/H, TTH/K, TKT/C, TKH/R, and TPS/H (Rsaliyev & Rsaliyev, 2018). Therefore, Sr11 and Sr36 are possibly effective against the majority of SR pathogen populations found in Kazakhstan.…”

“…Therefore, the prevention of SR is an important issue, requiring comprehensive genetic and breeding studies. Several experiments were conducted in Kazakhstan to search for sources of SR resistance in wheat germplasm ( Kokhmetova & Atishova, 2012 ; Shamanin et al, 2016 ; Rsaliyev & Rsaliyev, 2018 ). Nearly 60 Sr genes have been identified and cloned in wheat and its wild relatives ( Chen et al, 2018 ).…”

Genetic Variability of Perspective Btreeding Material of Spring Bread Wheat for Resistance to Leaf Rust in Russia and Kazakhstan

“…Winter wheat cultivars are grown in the southern regions of the country, and spring wheats -in the Northern, Western and Eastern regions. Developing high yielding and leaf rust, stripe rust and stem rust resistant cultivars is an important objective of winter and spring wheat (Triticum aestivum L.) improvement programs in Central and West Asia [4][5][6][7][8]. Production of wheat in Kazakhstan is being constrained also by leaf spotting diseases, including tan spot, caused by Pyrenophora tritici-repentis [9][10][11][12][13] and common bunt, caused by Tiletia caries [14].…”

Isogenic Lines: Reaction to the Kazakhstan Population of Stem Rust (Puccinia graminis f. sp. tritici)

“…A similar pattern was observed in 2016 and 2017. The spread of the pathogen was detected in all the examined fields in the northern Kazakhstan region, especially in the late wheat crops, and this resulted not only in a noticeable decrease in the yield but also in the worsening of the grain quality (Koyshybaev, 2018;Rsaliyev & Rsaliyev, 2018).…”