STUDY OF THE EFFECT OF OSMOTIC STRESS ON THE DROUGHT TOLERANCE OF SUDAN GRASS SAMPLES OF THE FSBSI “RUSSIAN RESEARCH, DESIGN AND TECHNOLOGICAL INSTITUTE OF SORGHUM AND CORN” SELECTION

Abstract

The success of selection in development of drought-tolerant samples largely
depends on the correct evaluation of the tolerance degree. The method of determining the
drought tolerance of Sudan grass samples in laboratory conditions is based on the unequal
ability of seeds to germinate under artificially modeled conditions with the help of osmotic
solutions. The studies were carried out in the laboratory of the FSBSI “Russian research, design and technological institute of sorghum and corn”. During the diagnostic of the Sudan
grass tolerance to stress, they were guided by a technique based on a positive connection between increased osmotic indices and drought tolerance. Sudan grass seeds were germinated in
sucrose solutions of different concentration. Drought tolerance was analysed by the length of
seedlings and roots of Sudan grass varieties. The most drought-tolerant samples of Sudan
grass are lines Laura, Faina, L-96-3/14 and varieties Mechta Povolzhia, Allegoriia, Zonalskaia 6. The content of absolute dry matter in the control variant: seedlings made 6.83-8.14%,
roots – 7.28-9.88%; in the experimental variant in seedlings – 8.05-27.07%, roots – 12.84-
38.71%. The redistribution of the growth intensity of the roots and seedlings in samples of
Sudan grass showed that the influx of assimilants mainly increased towards seedlings in the
control variant RSR=0.19-0.26. When seeds are germinated in different concentrations of sucrose, there is a strong variation in the values of RSR = 0.33-0.89 and the redistribution of
assimilants changes towards the accumulation of roots mass in comparison to germination in
distilled water. In the selection of optimal concentration of sucrose, it was found that the
highest value of linear indicators and the redistribution index of the growth intensity of roots
and seedlings on average for a group of samples of Sudan grass was revealed in the variant
with a concentration of 12 atm; linear indicators in a group of samples – 9 and 12 atm. An increase in the concentration of sucrose solution has an inhibitory effect on the size of the seedling and root; moreover there is a significant increase in the content of absolute dry matter.