The nature of fungal infection growth in varietal biocoenoses of winter rye and the search for resistant genotypes

Abstract

26 genotypes of winter rye from the selection of FASC of the North-East and 43 samples from the collection of the All-Russian Institute of Plant Genetic Resources named after N.I. Vavilov (VIR) were studied. Field studies were conducted in 2020–2022 in the conditions of the Kirov region on the natural background of fungal disease development in order to search for new genetic sources with complex non-specific resistance to fungal diseases. Disease monitoring (phases 31 to 85 on the Zadoks scale) allowed analysis of fungal infection build-up and identification of susceptible genotypes. Commonly known techniques were used to record the diseases. The nature of plant-microbial interactions and resistance parameters were evaluated by the AUDPC (area under disease progress curve) and the RI (resistance index) figures. By wax ripeness, only one collection sample, Rossiyanka 2, retained high resistance to septoriose in combination with the “slow rusting” trait. The AUDPC indicator was 105 units and the RI was 0.12. The given regression equations are linear in nature, on the basis of which it can be stated that daily increase of diseases according to the trend on the varieties of FASC of the North-East is 5.4...9.9% (brown rust) and 8.4...16.4% (stem rust); on the VIR collection samples – 6.4...12.1% (brown rust) and 15.0...45.0% (stem rust). The value of the coefficient of determination R2 = 90-99% is characterized as strong. Higher rust resistance of the FASС of the North-East varieties was noted in comparison with the studied samples of the VIR collection. 24 winter rye varieties with nonspecific resistance to two or more fungal diseases and slow “slow rusting” increase of infection during ontogenesis were identified (Flora, Grafinya, Perepel, Grafit, Grafit FP, Lika, Harmony, Symphony, Rumba large-grained, Wibro, Kaupo, Pastewne Zielone, etc.). These varieties can be used in breeding for increasing phytoimmunity to specific diseases as the trait sources.