Evaluation of the oats varietal reaction to soil drought by the chlorophyll index

The purpose of the study is to evaluate the use of chlorophyll index values obtained through rapid diagnostics in the selection of promising genotypes for the selection of drought-resistant oat varieties. For research in 2020-2022 40 varieties of oats of domestic selection were used. The experiment was carried out in greenhouse conditions, where soil drought was artificially created during the period of tillering and flowering. A comparison of the response of varieties to soil drought was carried out by calculating the degree of decrease in the chlorophyll index relative to the control, as well as by calculating the decrease in oat biomass. It has been established that oats respond maximally to soil drought during the flowering period. A minimal decrease in the chlorophyll index was recorded in the varieties Peredovik, Sig, Chisch, CROSS, Horizont, Privet, Barguzin, which can be used as valuable breeding material for creating drought-resistant varieties. Their chlorophyll index decreased during drought during tillering by 6.1-8.7 %, and during flowering by 3.7-5.1 % against the background of a general decrease in the collection of 13.0 and 7.8 %, respectively. Varieties Pokrovsky 9, Tigroviy, Tayoschnik, Avatar, Talisman, Express, Narymsky 943, Orion, Bulany, Tubinsky had the strongest decrease in the chlorophyll index, which indicates the manifestation of severe stress caused by soil drought. A correlation was established between the degree of decrease in the chlorophyll index and plant biomass under the influence of soil drought during tillering (r = -0.65) and flowering (r = -0.55). The chlorophyll index values depend 46% on the genotype and 35 % on stress caused by soil drought.