ECOLOGICAL STABILITY MAIZE HYBRIDS RELATIVELY GRAIN YIELD IMPORTANT CONDITION INCREASE IN GROSS PRODUCTION

The relevance of the conducted scientific analysis of long-term data of the competitive test of the State Institution Institute of Grain Crops of the NAAS, regarding the grain yield of maize hybrids, is due to the problems of climate change that has been observed. Due to an increase in air temperature and a long without a frosty period, corn is not only guaranteed to ripen in the Steppe, with timely sowing and harvesting, but also has a harvest moisture content of grain close to the base. Corresponding climate changes motivated the rapid expansion of the territory of corn cultivation in Ukraine, an increase in acreage, gross production, and grain yield of this crop. However, the dangers caused by stress factors of the flight period are increasing, which focuses on the problem of creating hybrids that are resistant to the extreme conditions of the northern Steppe. Due to the determination of the parameters of the tolerant types, models of hybrids were formed and recommended for use in production in the conditions of various ecological territories of Ukraine. The article discusses the results of the progress of the yield of corn hybrids due to breeding improvement, reflected in changes in the actual indicators of grain harvest and harvest moisture of grain caused by climate change and their impact on the elements of crop cultivation technologies. It was determined that under stressful conditions, the grain yield of maize hybrids decreased by an average of 2.9 t / ha, and the harvest moisture content of the grain increased by 1.6%. It was also noted that over the past 25 years, the yield of corn grain in the test, on average for a five-year period, increased from 5.69 (1995-1999) to 7.14 t / ha (2016-2020) with a decrease in the harvest moisture content of grain from 22.4 to 16.1%. In the discussion of the research results, the regularities of the formation of the trait "drought resistance" of hybrids are revealed, the genetic and agrotechnological components of the formation of the trait, their influence on the characteristics of crop cultivation are distinguished. As a result, the value of a hybrid with an average but stable grain yield, which is determined by economic feasibility, is proved, in comparison with high-intensity forms, which are characterized by significant fluctuations. In order to obtain high and stable yields of corn grain in each farm, it is necessary to plan the varietal structure of crops with an assortment of hybrids that have a diverse type of reaction to the variability of environmental conditions.