Productivity of Winter Wheat Cultivated by Direct Seeding: Measuring the Effect of Hydrothermal Coefficient in the Arid Zone of Central Fore-Caucasus

In arid zones, the yields of soft winter wheat varieties are particularly affected by the variations of hydrothermal conditions. This especially applies to direct seeding practices, for which the understanding of the links between hydrothermal parameters of soil and the environment, on one side, and the productivity of winter wheat, on the other, is one of the founding pillars of stable agricultural systems. On the case of the arid zone of Central Fore-Caucasus, this study investigates changes in the duration of interphase periods of plant development, plant density, and yield. It is found that in 2019–2021, positive temperature shifts and drought resulted in an increase in the duration of the growing season of crop varieties, thinned plant density, and reduced productivity of drought-resistant varieties. Evaluation of indices, that determine the ecological and genetic variability of varieties in the “genotype-environment” system resulted in the establishment of models that described the effect of drought on crop yields by type of manifestation and forecrops (sunflower, chickpeas). It is shown that the average linear deviations improved phase techniques and changed the area of winter wheat cultivation. On the back of the further drought propagation, farmers in arid zones could benefit from breeding new varieties and hybrids of grain crop. These measures may increase or stabilize the productivity of winter wheat in arid environments. Specifically, for the arid zone of Central Fore-Caucasus, the study recommends reducing lands under grain crop and shifting the cultivation of winter wheat northward. This will reduce the impact of volatile climatic conditions on winter wheat productivity in the region.