Estimation of drought resistance of self-pollinated maize lines by the residual water deficit method

Relevance . Breeding for drought resistance is one of the most important areas of maize breeding due to the increasing climate aridity and the location of maize crops in areas with unstable and insufficient moisture. Methods . Field and laboratory trials were conducted at the “Agricultural Research Center “Donskoy” in 2011–2013, 2015–2023. Field trials were laid out according to the Methodology of Field Trials with Maize. The soil of the experimental plot was ordinary blackearth (chernozem), with a 140 cm of humus layer thickness. The climate was moderate continental with unstable moisture. The years of the study were characterized by different degrees of aridity (HTC 0.32–0.87). The objects of the study were 155 new constant self-pollinated maize lines. The estimation of drought resistance was carried out by the residual water deficit method. Results . There have been identified fifty-six drought-resistant self-pollinated maize lines with low values of residual water deficit (RWD) in the flowering phase (4.6–13.3%) and in the milky-wax ripeness phase (6.8–14.2%). The RWD value depended not only on the lines, but also on the conditions of the year of the trial. There has been established a tendency for residual water deficit to increase in hot and dry years. There has been identified an average negative correlation (r = -0.44) between the value of the RWD in the flowering phase and the average daily air temperature in July; between the water deficit value in the milky-wax ripeness phase and the average daily air temperature in August (r = -0.65). There have been revealed low but reliable correlation coefficients (r = -0.24…-0.27) between the RWD and the amount of precipitation in different periods of maize development.