Selection of soybean genotypes tolerant to charcoal rot, based on the ontogenetic dynamics of cellular juice’s osmotic pressure in vegetative tissues

A description is given of a study of the daily rhythm of osmotic pressure of cell sap (ODCS) in plant tissues in soybean varieties of early ripening and mid-ripening groups. It was found that the most reliable is the estimation of ODCs in any aboveground part of plants in the morning hours or only in the lower tier of plants, but during the first half of the day. On the basis of studies of circadian rhythm and ontogenetic dynamics of ODKS, a method has been developed for selecting an ash-tolerant source material for soybean selection that is tolerant to infection. The method is based on the isolation of plant forms with osmotic pressure of the cell sap not exceeding 930 kPa in critical for water consumption phase of bob formation and seed filling.