ESTIMATION OF HEAT RESISTANCE OF OILSEED RADISH BY LABORATORY METHODS

Abstract

The article reflects the results of studying the peculiarities of the study of drought and heat resistance of three zoned varieties of oil radish, based on widely tested methods applied to a number of other agricultural crops. The viewpoints of many researchers on the processes of forming the temperature stress adaptations of plants have been systematised, taking into consideration the mechanism of drought and heat resistance and its role in providing the development of adaptive elements of the technology for growing cruciferous crops and climatic changes in the growing season in the area of economic distribution of oilseed radish. The peculiarities of the application of two laboratory techniques simultaneously have been studied. One of the methods is based on stress reactions of seeds with an assessment of the level of its germination after preliminary long-term heating of the wetted seeds by gradually increasing high temperatures. The second technique is based on the temperature reaction of the assimilation apparatus of plants to an environment with different temperatures in order to determine the degree of destructive effect of high temperatures on leaf structures with the subsequent determination of the degree of damage to the studied samples by staining the affected areas in the appropriate chemical environments. The application of this methodology has made it possible to determine that the threshold temperature value for forming the standard permissible levels of laboratory germination of seeds in the studied varieties of oil radish is in the range of 35-45 °C. The actual intensive decrease in laboratory germination for seeds with one-year biological age in the studied varieties of oil radish has been distinguished for the temperature regime of heating at 60 °C and higher with a zero level of laboratory germination at 80 °C. Considering the short heating period of pre-soaked seeds, oil radish plants are able to withstand a short-term increase in air temperature with sufficient soil moisture in the confidence range of 40-55 °C. Considering the decrease in laboratory germination for seeds of biological age 1-5 years already starting from the level of preliminary heating at a temperature of 30 °C – the optimum germination of oilseed radish varieties and the optimal growth and development of oilseed radish plants in conditions of sufficient soil moisture was most likely in the range of 20-25°C. Based on the results of the application of these methods in relation to drought and heat resistance, the studied varieties of oilseed radish can be placed in the following order of decreasing of the indicator ‘Raduga’-‘Zhuravka’-‘Lybid’. The prospects for further research in the field of optimizing drought and heat resistance diagnostics by laboratory methods have been formulated. Key words: oilseed radish, drought resistance, heat resistance, germination, temperature adaptation.