Повышение эффективности отбора яровой пшеницы на устойчивость к почвенным инфекциям

The aim of the research was to substantiate the need to take into account the factors that have a significant impact on the root rot infestation of spring wheat in the process of practical selection for resistance. The studies were carried out in 2019–2020 with the application of generally accepted and author’s methods. A systemic restructuring of work is needed to increase the efficiency of practical breeding for resistance to root rot. The damaging factor is cereal flies which “open the gates” to all soil phytopathogens after the tillering phase. It should be eliminated, and the ability of varieties to induce the suppression of rhizosphere soil to main phytopathogens should be taken into account. According to the results of two years of research, the smallest, within two biological thresholds of harmfulness (PV), the infestation by root rot at the germination phase was shown by the spring wheat varieties Novosibirskaia 15 and Manu. The development of root rot in comparison with the germination phase in 2019 increased by an average of 2.5, and in 2020 - by 5.6 times. There was an equalization of differences in damage between varieties during the growing season. In the germination phase, the coefficient of variation in the development of root rot by varieties was 24.1 ± 4.0, in the phase of maturity, it decreased 2.5 times to 9.4 ± 1.5. The main reason for smoothing out the differences between varieties in terms of root rot infestation was strong (up to 100%) damage by intra-stem pests. The economic threshold of harmfulness for damage to spring wheat stems by cereal flies was exceeded in 2019 up to 4.8 times, and in 2020 up to 7.8 times. The correlation coefficient between the development of root rot and damage by intra-stem pests in 2019 was R = 0.744 ± 0.185 (P <0.01), in 2020 R = 0.713 ± 0.092 (P <0.01). Analysis of variance showed that the power of the influence of the spatial arrangement of plants on their damage by cereal flies was 30.9% and was reliable at the 1% level, while the influence of the variety itself on this indicator was almost 2 times lower (16.8%) and was significant at the 5% level. The induction of soil suppression to phytopathogens by the rhizosphere of spring wheat varieties influenced their representation in the pathogenic complex of root rot. The correlation coefficient of induction by cultivars of suppressiveness to F. poae and its representation in pathogenic complexes was R = - 0.638 ± 0.318 and was significant at the 5% level. The correlation coefficient of induction of suppressiveness to F. oxysporum and its presence in pathogenic complexes of root rot of varieties was R = - 0.844 ± 0.203 (P <0.01).