Pyrenophora tritici-repentis population structure in the Republic of Kazakhstan and identification of wheat germplasm resistant to tan spot

Abstract

Pyrenophora tritici-repentis is a causative agent of tan spot in wheat. In recent years, there has been an increasing spread and harmfulness of wheat tan spot. The aim of the research was to study the racial composition of the P. tritici-repentis population in the Republic of Kazakhstan. A collection of 30 common wheat accessions, including promising lines and cultivars from Kazakhstan and CIMMYT–ICARDA, was assessed for resistance to P. triticirepentis in a greenhouse and characterized using the Xfcp623 molecular marker, diagnostic for the Tsn1 gene. Monosporic isolates of P. tritici-repentis isolated from the southeastern region were assigned to certain races based on the manifestation of symptoms of necrosis/chlorosis on standard differentials (Glenlea, 6B662, 6B365). Five races of P. tritici-repentis have been identified, including races 1, 2, 3, 7 and 8. It has been shown that races 1 and 8 of P. tritici-repentis are dominant. As a result of the analysis of the frequency of occurrence of the P. tritici-repentis races, it was found that race 1 (50 %) producing Ptr ToxA and Ptr ToxB and race 8 (35 %) producing Ptr ToxA, Ptr ToxB and Ptr ToxC turned out to be dominant. From a practical point of view, of greatest interest are 16 wheat samples, which demonstrated resistance to race 1 and confirmed insensitivity to Ptr ToxA in a molecular screening. These include eight Kazakhstani (4_PSI, 10204_2_KSI, 10204_3_KSI, 10205_2_KSI, 10205_3_KSI, 605_SP2, 632_SP2, Dana) and seven foreign lines (KR11-20, KR11-03, KR11-9014, 11KR-13, KR12-9025, KR12-07, GN-68/2003). The results of this study are of interest in wheat breeding programs for tan spot resistance.

Characterization of Pyrenophora tritici-repentis (tan spot of wheat) races in Kazakhstan

“…Lamari et al (1998) were the first to report race 5 in Algeria, and this race has since been reported in Canada (Strelkov et al, 2002), the United States of America (Ali et al,1999), Syria and Azerbaijan (Lamari et al, 2005b). In contrast, race 6 was found in Algeria and Morocco (Strelkov et al, 2002;Benslimane, 2018;Gamba et al, 2017), while races 7 and 8 were found only in the Middle East, Caucasus and Algeria, and Kazakhstan in 2018 and 2020 (Kokhmetova et al, 2020b;Benslimane, 2018, Ouaar et al, 2022. In 2021, in the North Caucasus region of Russia, races 1, 3 and 4 were identified (Kremneva et al, 2021).…”

“…The race population structure of P. tritici-repentis in Kazakhstan has had large fluctuations in recent years (Kokhmetova et al, 2016b., Kokhmetova et al, 2020b. Population structure and race composition of the pathogen has been studied in many geographic regions in the world.…”

“…As previous varies in different years in Kazakhstan by geographical and climatic zones, and in recent years it has become more widespread globally. The races 1, 3, 4, 6 and 8 were identified in 2013-2015(Kokhmetova et al, 2016bKokhmetova et al, 2017), and races 1, 2, 3, 7 and 8 in 2018 (Kokhmetova et al, 2020b). In both years, races 1 and 8 were dominant.…”

Identification of Stripe Rust Resistance Genes in Common Wheat Cultivars and Breeding Lines from Kazakhstan

“…f. sp. tritici and leaf rust caused by Puccinia triticina Erikss [2-8], as well as leaf spot diseases (tan spot and Septoria) [9][10][11][12][13][14].…”

Evaluation of Wheat Germplasm for Resistance to Leaf Rust (Puccinia triticina) and Identification of the Sources of Lr Resistance Genes Using Molecular Markers

“…One of the main reasons for the reduction in the yield of wheat in Kazakhstan is the disease with airborne infection. Dominant position, as a part of the pathogenic complex of wheat in Kazakhstan, is taken by rusts (yellow, stem, and leaf rust) [2][3][4][5], as well as leaf spot diseases (tan spot and Septoria) [6][7][8][9][10][11].…”