EFFECTS OF THE DWARFING GENE ALLELES ON COLEOPTILE LENGTH OF BREAD WHEAT UNDER OSMOTIC STRESS CONDITIONS
One of the critical periods of plant response to drought is the germination stage. Deviations from the optimal conditions of growth in the period of germination negatively affect the development of wheat plants in the following stages of ontogenesis. Сoleoptile length is indirectly involved into the development of drought resistance of bread wheat at the germination stage. The aim of our study was to evaluate the effect of gene alleles Rht8, Rht-B1, Rht-D1 on the coleoptile length of the analogue lines, which differ in Rht alleles, during germination under osmotic stress. Osmotic stress was simulated by using a 15 % PEG-6000 solution. Stressful conditions were applied for 7 days from the germination beginning. Genotypes without Rht genes were characterized by longer coleoptile compared with dwarfing forms on the control and PEG solution. The difference of coleoptile length between the parental tall forms and lines-analogues was lower in the control than in the osmotic stress conditions. It has been found that coleoptile length of analogue lines is shorter in comparison with tall forms under osmotic stress conditions and depends on alleles: Rht8c (25.4 and 26.9 % (on different genetic backgrounds), Rht-B1b (30.3 %), Rht-B1e 31 and 42.1 % (on different genetic backgrounds), Rht8c+Rht-B1e (58 %), Rht8c+Rht-B1b (61.6 %), and Rht8c+Rht-D1b (25.1 %). It was shown that coleoptile length also depends on the genetic background.