The effect of long-term edaphic stress on the characteristics of next generation of spring wheat hybrids seedlings

A new genetic material of spring wheat (15 hybrid populations) developed within the breeding work for aluminum resistance, was studied in the field and laboratory conditions. Studies of F4 hybrids were carried out on soils that differ in the pH level and in the content of mobile aluminum ions. Strong edaphic stress on background 2 (pH = 3.8; Al3+ content = 211 mg/kg of soil) caused a sharp decrease in yield (by 88.2 %) and productivity traits (by 18.5...63.8 %) compared to background 1 (pH = 4.3; Al3+ = 5.4 mg/kg of soil). Laboratory analysis determined the influence of the reproduction conditions of the previous generation on the parameters of the root system of seedlings, their biomass and the root/sprout ratio (RSR index) in the offspring F5. The seeds were germinated in distilled water (control) and an aqueous solution of aluminum sulfate (experiment). It was shown that the weight of seedlings was significantly more strongly influenced by reproduction conditions (an average decrease of 26.1 %) than artificially created stress (a decrease of 2.3...4.7 %). The majority of hybrids showed a significant increase (by 3.9...16.4 %) in laboratory resistance according to the root length index (IDC) as an adaptive response to prolonged edaphic stress. The recommendation is given to take into account the growing conditions of the previous generation, since under their influence the reactions of genotypes by seedling weight, RSR index, as well as correlations between traits can change. The differences of genotypes in the potential level of traits and their stability in different environments were revealed. The hybrid Karabalykskaya 98 x Lutescens 30 differed in the length of the roots, Baganskaya 95 x Gornouralskaya – in the weight of the seedling. The hybrid Baganskaya 95 x Jasna was characterized by the greatest stability according to a set of parameters. Hybrids with potentially longer roots and high seedling mass showed greater sensitivity to changes in environmental conditions. Genotypes with a predominance of the aboveground part in the control were characterized by a more stable "root/sprout" ratio.