Juvenile resistance of wheat varieties and lines Developed by the far eastern SAU to leaf and stem diseases

The current study was conducted to estimate the resistance of zoned spring common wheat varieties and lines developed by the Far Eastern SAU to the pathogens of leaf blotch, brown and stem rust, dark brown blotch and net blotch; as well as to identify dominant/recessive alleles of the Tsn1 and Snn1 genes in the genotype of varieties. Immunological tests of common wheat varieties and lines were conducted in the laboratory conditions at the All-Russian RI of Plant Protection (VIZR, St. Petersburg) and the FARC of South-East (Saratov) in 2025. The objects for the study were 6 spring common wheat varieties and 6 lines developed by the Far Eastern SAU. As a result, there have been identified different resistance levels of the samples to pathogens. Resistance to Zymoseptoria tritici was shown by 2 varieties (‘DalGAU 2’, ‘Amurskaya 1495’) and 3 breeding lines (‘KSI-6-24’, ‘KSI-21-24’, ‘KSI-26-24’). The line ‘KSI-25-24’ has demonstrated resistance to Parastagonospora nodorum . Three lines ‘KSI-6-24’, ‘KSI-21-24’ and ‘KSI-25-24’ were resistant to P. pseudonodorum . High resistance to Septoria triticicola was demonstrated by the lines ‘KSI-6-24’ and ‘KSI-21-24’, and the variety ‘Amurskaya 90’ and the lines ‘KSI-22-24’ and ‘KSI-25-24’ showed ordinary resistance. Using the molecular markers Xfcp623 and Xfcp624 , which determine plant sensitivity to the toxins of P. nodorum and P. pseudonodorum ( ToxA and Tox1 ), there has been established that the varieties ‘DalGAU 1’, ‘DalGAU 2’, ‘DalGAU 4’, ‘Amurskaya 90’ and ‘Amurskaya 1495’, as well as the lines ‘KSI-6-24’, ‘KSI-22-24’ and ‘KSI-25-24’ have protection from T oxA due to the recessive t sn1 allele. The variety ‘DalGAU 4’ and the lines ‘KSI-21-24’, ‘KSI-22-24’ and ‘KSI-25-24’ carry the recessive snn1 allele, providing protection from the toxin Tox1 . In addition, the varieties ‘DalGAU 3’ and ‘DalGAU 4’, as well as the lines ‘KSI-6-24’, ‘KSI-22-24’ and ‘KSI-25-24’ have demonstrated moderate resistance (MR) to leaf rust. The variety ‘Amurskaya 1495’ and the line ‘KSI-35-24’ have shown moderate resistance (MR), while the line ‘KSI-26-24’ showed resistance (R) to stem rust. Four varieties ‘DalGAU 1’, ‘DalGAU 2’, ‘Amurskaya 90’, ‘Amurskaya 1495’ and one breeding line ‘KSI-26-24’ have demonstrated a resistant reaction (R) to Pyrenophora tritici-repentis . The varieties ‘DalGAU 3’ and ‘DalGAU 4’, as well as the lines ‘KSI-22-24’ and’ KSI-25-24’ have shown resistance to Bipolaris sorokiniana at the sprouting stage.