FORMATION OF SPRING BARLEY PRODUCTIVITY UNDER STRESSFUL CONDITIONS

A comparative study of barley varieties by the main elements of productivity on a short (10-hour) light day was carried out. The aim of the research was to search for and improve methods for assessing and selecting genotypes of spring barley, maximally adapted to local weather conditions. The research materials were varieties of steppe and Western European origin in comparison with the breeding lines of the competitive variety testing (CVT). Productive bushiness on a short day was significantly reduced in western varieties and amounted to 40.9% of the control variant, in steppe varieties and lines the indicator is higher – 60.1 and 59.4%, respectively. The number of plants planted on a short bottom was the highest (54.9%) in the group of steppe varieties, in the group of Western European varieties this indicator was the lowest - 30.8%, the CVT lines occupy an intermediate position – 45.9%. This indicator is positively correlated with the elements of productivity in the 1st replanting: ґ = 0,45** - 0,80***, weakly correlates with the mass of 1000 grains in the second re-sowing: ґ = 0,32* - 0,34* . The indicators of the mass and number of grains in the ears formed on a short day are negatively related to productivity in 2021: in the control variant, ґ = -0.60**, in sowing from plants grown on a short day, ґ = -0.68**. In steppe varieties and CVT lines, the restoration of all studied indicators was noted already the following year, with an excess over the control of grain weight from the ear or productive bushiness. A significant increase in productivity from the selected ears was noted in steppe varieties of local origin, i.e. it can be assumed that they have biotypes with neutral photoreaction alleles. The short- day factor contributes to the inhibition of the physiological processes of plant formation, thereby probably stimulating the predominant development of late-maturing, high-potential genotypes. These assumptions can be successfully used in the breeding process when selecting productive barley lines adapted to the conditions of the region.