Genetic basis of spring wheat resistance to leaf rust (Puccinia triticina) in Kazakhstan and Russia

Authors: MORGOUNOV, ALEXEY - Russian Agrarian University; POZHERUKOVA, VIOLETTA - Russian Agrarian University; Kolmer, James; GULTYAEVA, ELENA - Almaty; ABUGALIEVA, AYGUL - Almaty; CHUDINOV, VLADIMIR - Almaty; KUZMIN, OLEG - Omsk State Agrarian University; RASHEED, AWAIS - Quaid-I-university Islamabad; RSYMBETOV, ASKHAT - Almaty; SHEPELEV, SERGEY - Russian Agrarian University; YDYRYS, AIKERM - Almaty; YESSIMBEKOVA, MINURA - Almaty; SHAMANIN, VLADIMIR - Russian Agrarian University

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2020
Publication Date: 10/8/2020
Citation: Morgounov, A., Pozherukova, V., Kolmer, J.A., Gultyaeva, E., Abugalieva, A., Chudinov, V., Kuzmin, O., Rasheed, A., Rsymbetov, A., Shepelev, S., Ydyrys, A., Yessimbekova, M., Shamanin, V. 2020. Genetic basis of spring wheat resistance to leaf rust (Puccinia triticina) in Kazakhstan and Russia. Euphytica. 216. Article: 170. https://doi.org/10.1007/s10681-020-02701-y.
DOI: https://doi.org/10.1007/s10681-020-02701-y

Interpretive Summary: Wheat leaf rust caused by the fungus Puccinia triticina, is an important disease of wheat in the USA and worldwide. Leaf rust can be very severe in continental regions such as the Great Plains of the USA and also in the Russian region of Siberia and in Kazakhstan in Central Asia. At present there are over 79 identified genes for leaf rust resistance wheat, however many of these genes no longer give good resistance due to the presence of highly virulent leaf rust races. The objectives of this study were to identify which genes for leaf rust resistance are in 120 spring wheat cultivars from Russia and Kazakhstan. The cultivars were tested for resistance with eight different races of P. triticina from the USA and six races from Russia that differ for virulence to important leaf rust resistance genes. All cultivars were also tested in field plots for leaf rust resistance. Molecular DNA markers genetically linked to important leaf rust resistance genes were also used to determine the presence of resistance genes in the cultivars. Eleven different leaf rust resistance genes were postulated to be in the cultivars. Gene Lr19 had the largest effect on giving good resistance. The important resistance gene Lr34 was identified in 11 cultivars. These results can be used by wheat breeders and plant pathologists to help select wheat germplasm that has good resistance to leaf rust.

Technical Abstract: Kazakhstan-Siberia Network for Spring Wheat Improvement (KASIB) was established in 2000 and comprises 18 breeding and research programs. The network conducts multi-location cooperative yield trials to exchange the material and evaluate agronomic traits. In 2016 all the data was analyzed and 120 cultivars and breeding lines demonstrating different degree of resistance to leaf rust were selected. The cultivars and lines were tested for leaf rust, other diseases and agronomic traits in Russia, Kazakhstan and Turkey in 2017-2019. Leaf rust gene postulation was conducted in Russia and USA using 14 different pathotypes and molecular markers. All the germplasm was grouped into four categories based on leaf rust reaction in Omsk in 2018: 31 resistant (R), 27 moderately resistant (MR), 37 intermediate (M) and 25 moderately susceptible (MS) entries. The Lr genes were postulated based on tests using pathotypes with known virulence profiles and molecular markers. The most frequent Lr genes alone or in combination were Lr10 (31 entries), Lr26 (24), Lr9 (23), Lr1 (18), Lr17 (11), Lr34 (11) and Lr19 (7). Genes Lr14a, Lr24, Lr37, Lr39 and Lr66 were identified in 1-2 genotypes each. Genes Lr1, Lr9, Lr10 and Lr17 reduced the leaf rust severity to M or MS in Omsk in 2018 and other environments. The presence of Lr26 alone or in combination with other major genes reduced the leaf rust severity to MR-M in Omsk and R in Sakarya, and was less effective in Almaty, Kazakhstan. The only gene with the large effect on leaf rust was Lr19, which provided a high level of resistance at all sites both alone and in combination with Lr26. Leaf rust severity of 52 entries with adult plant resistance was compared to 68 entries possessing effective seedling genes. The leaf severity of entries with adult plant resistance (APR) compared to seedling resistance was similar at low infection pressure at Sakarya, 2017 and Omsk, 2019. However, at higher leaf rust leaf rust infection levels at Omsk in 2017 and 2018, and Almaty in 2019, there was clear resistance advantage of the germplasm possessing major genes. There was also variation within both groups: nine lines out of 31 from the R group were classified as having APR resistance and demonstrated low severity across most of the sites. High level of stem rust infection in Omsk in 2019 confirmed effectiveness of the Sr31/Lr26 gene. A set of 33 genotypes was selected combining resistance to leaf and stem rust with superior agronomic performance.