Influence of hydrothermal regime on spring wheat yield in the conditions of the Republic of Tuva

The objective of the study is to investigate the influence of climatic conditions on the yield of spring wheat varieties in the Republic of Tuva. The paper presents the results of three-year studies of soft spring wheat varieties Altayskaya 75 and Novosibirskaya 31 in the forest-steppe zone of the Republic of Tuva. The influence of temperature and precipitation on yield formation and 1000-grain weight was determined. A positive relationship was established between yield and precipitation during the period of active plant growth (tube emergence - heading) (r = 0.48). The amount of precipitation in June showed a positive closeness of the average relationship with yield and 1000-grain weight. Precipitation in August had a negative effect on yield formation and 1000-grain weight, showing a close inverse relationship (r = -0.74 and r = -0.71). June temperature positively correlates with yield and 1000-grain weight (r = 0.39, r = 0.44). The temperature of July is highly correlated with the yield (r = 0.79), but shows an inverse relationship with the 1000-grain weight (r = -0.74). The temperature of August has a weak positive relationship with the yield and the 1000-grain weight. In general, the hydrothermal regime of June has a high relationship with the yield, a medium-strength relationship with the 1000-grain weight. The July hydrothermal regime is positively associated with the yield and medium-strength with the 1000-grain weight. The revealed instability of the yield of spring wheat Altai 75 over time is attributed by us to the manifestation of the genotype, i.e. to the biological characteristics of the variety.