Adaptive reactions of wheat seedlings differentiating varieties under hyperthermia

Abstract

When creating varieties, adapted to temperature stress factors, it is necessary to carry out diagnostics of their resistance to stress factors. Diagnostic methods should have high differentiating ability in reliably distinguishing the resistance of closely related objects, such as varieties from the same crop or plants from the same variety population. To ensure the differentiating ability of the method, the assessment of resistance diagnostics towards stress factors should be conducted with the same strength of stress load and modes of stress factors that would enable to range varieties. In model laboratory vegetation experiments, the adaptive reactions of 10-day-old seedlings of three varieties of spring wheat were assessed according to changes in growth rates, wet and dry biomass, and permeability of cell membranes of seedlings under hyperthermia (warming the seeds) with the purpose of identifying the temperature that differentiates varieties. The seedlings were grown in roll culture on tap water in a climate chamber with preset parameters of microclimate. Before that, the seeds were pre-heated in hot water in thermostat at temperatures of 30, 43 и 54°C. The seedlings of control variety were cultivated in the same conditions without warming the seeds. The formation of adaptive reaction to hyperthermia of seeds differed across varieties of seedlings of spring wheat varieties Novosibirskaya 18, Novosibirskaya 44 and Omskaya 18. Adaptation of varieties to similar temperature factors formed in different ways, which can be explained by hereditary nature of plants. According to the results of the research, the maximum values of variation coeffi cient of biophysical and biometric indicators of seedlings was identifi ed at the temperature of 43°C. This is the differentiating temperature in assessment of wheat crop varieties adaptation to the increased temperature. This temperature was applied in experiments to study the reaction of wheat varieties to separate and joint effects of chloride salinity, seed infection with common root rot and hyperthermia.