Influence of snow mold on winter rye productivity in the Kirov region

In the conditions of the Kirov region, the major factor reducing the productivity of winter crops is infestation with snow mold (Microdochium nivale (Fr.) Samuels et. Hallet. - synonym Fusarium nivale (Fr.) Ces.), which annually grows by 80-100%. Therefore, the main direction of breeding is receiving winter rye varieties having maximum resistance to this disease. During the period of 2003-2017 there was carried out the assessment of zoned and perspective cultivars of domestic breeding of various ecological-and-geographical origin for snow mold infestation in natural provocative conditions. Weather conditions differed greatly in all periods of rye development. It has been established that plant resistance to M. nivale pathogen is influenced greatly by the condition of plants before wintering regulated by the sowing time. Well-developed plants of Falenskaya 4 variety formed the optimum density of an agro-phytocenosis, accumulated bigger amount of sugars (more than 7%), regenerated during spring re-growth by more than 90%, and produced stable high yield (more than 4.9 t/ha). In order to realize the biological potential of the variety, there was a need to shift the previously established sowing time to 5-10 days later period. The productivity was influenced greatly by April conditions, namely, by the period of total clearing of sowings from snow, which took only several days (3-6). Warm and dry weather favored an active re-growth of rye and prevented disease development. Cold and damp weather provoked fungus development, which affected quickly the plants weakened after rewintering. It was revealed that winter rye varieties of different ecological-and-geographical groups responded to this disease differently. The variability in productivity of each cultivar by years was high (CV = 25.8…65.4%). The greatest stability was characteristic for varieties bred in FARC North-East. The main methods of breeding for the resistance to snow mold are crossing and selection in the conditions of a provocative background. The efficiency of a selection method is confirmed with creation from Falenskaya 4 a highly winter-hardy variety Flora with active regeneration after snow mold infestation (100%) and stable productivity by years – 4.62 t/ha (addition yield to an initial cultivar was 0.27 t/ha). The distinctive feature of Flora variety is active formation of powerful green mass in spring that is important for the early use for green forage for cattle and poultry. Since 2012 the variety is included in the State Register of breeding achievements in Volga-Vyatka and North-West regions of the Russian Federation.