S u m m a r yThe estimation was made for 18 variants of octaploid winter wheat-Аgropyron hybrids (WAH) (2n = 56) on juvenile resistance to 10 isolates of leaf rust. By the use of molecular markers the presence of different subgenomes of Thinopyrum sp. in investigated variants was shown. In variants of WAH the authors revealed a polymorphism on resistance to test-isolates of leaf rust, which may be due to various number of agropyron chromosomes in genome. The authors discussed the possibility of using studied WAH in breeding on resistance to leaf rust and the role of resistance in improvement of economical-valued determinants of WAH in breeding process.Keywords: wheat, wheat-Thinopyrum hybrids, leaf rust, resistance genes.Leaf rust (Puccinia triticina Eriks.) is the cause of a significant damage to wheat (crop loss up to 50 %), especially in southern regions of Russia (1). Over 50 genes for rust resistance have been detected (2), and molecular markers have been developed for many of these genes (3). Very often sources of such genes are wild relatives of wheat. In particular, genes Lr24, Lr29, and Lr19 of Thinopyrum ponticum (genomic constitution JJJJsJs, 2n = 70) and Lr38 gene of Th. intermedium (genomic constitution JSJs, 2n = 42) were transferred into wheat through intergeneric hybridization in order to provide its resistance to many races of the pathogen (4). The emergence and spread of new races weakens the resistance caused by these genes (5-7), that's why it is important to find new genes for complete or partial resistance to leaf rust of wheat that will help to develop a pyramidal system of cultivars' resistance. Besides, introduction of new genes to commercial wheat varieties through hybridization will retard host-parasite co-evolution.Hybrids of wheat and Agropyron (Th. intermedium) are seen as a promising source of new genes for rust resistance. In this regard, there's a great potential in the collection of wheat-Agropyron hybrids (WAH) developed in the Department of distant hybridization of Tsitsin Main Botanical Garden (RAS) by crosses of wheat (both soft and durum) with different Agropyron species (including intermediate and tall wheat grass). These hybrids have long loose ear typical for perennial wheat and manifest various types of perennial life cycle and regrowth after mowing. Earlier the authors have shown octaploid (2n = 56) nature of these plants (8).One of important steps in creation of new resistant wheat forms is immunological evaluation (9). The abovementioned WAH weren't subject to phytopathological analysis, and relative resistance of these forms was evaluated only in field observations, which are strongly influenced by the environment (10).The purpose of this work was screening of the collection of winter wheat-Thynopyrum hybrids for the presence of Thynopyrum genome and leaf rust resistance.Technique. The studied samples were winter WAH Istra 1, Zernokormovaya 169, Ostankinskaya, Otrastayuschaya 38, ¹¹ 12, 33, 77, 90, 116, 186, 548, 1405, 1670, 2087 (Department of distant hybridizatio...

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