Response of Italian Ryegrass (Lolium multiflorum L.) Cultivars to Different Drought Levels

Abstract

This study is aims to determine the germination and seedling growth responses of Italian ryegrass (Lolium multiflorum L.) cultivars under drought stress. The research was conducted in the Laboratory of the Department of Field Crops, Faculty of Agriculture, Siirt University. The plant material used in the study consisted of three Italian ryegrass cultivars Çiğdem, Elif, and Zeybek-19. These cultivars were germinated under different drought levels (0%, 5%, 10%, 15%, and 20%). The laboratory experiment was conducted with a randomized split-plot design, with four replications. In the study, germination percentage (GP), mean germination time (MGT), germination index (GI), germination of uniformity coefficient (CUG), germination energy (GE), seedling fresh weight (SFW), and seedling vigor index (SVI) parameters were examined. The increase in drought levels significantly (p<0.01) affected the germination and seedling characteristics of the Italian ryegrass cultivars. The cultivars had a statistically significant effect (p<0.01) on the GP, GE, SFW, and SVI. The drought values of the GP, MGT, CUG, GI, GE, SFW, and SVI parameters ranged from 49.8-89.8%, 1.9-3.4 days, 15.0-49.0, 4.8-15.8, 4.4-47.6, 22.3-38.0 mg, and 1.1-3.4, respectively, while the variety averages varied between 70.9-78.7%, 2.1-2.2 days, 38.5-40.4, 12.3- 12.6, 28.0-38.4, 28.3-33.5 mg, and 2.1- 2.7, respectively. The effects of drought stress were observed in the germination and seedling growth parameters starting from the 10% drought level. According to the results of the study, the stress tolerance exhibited by the cultivars in response to drought levels also varied. Among the Italian ryegrass cultivars Çiğdem and Elif were more tolerant to drought in terms of germination and seedling growth parameters compared to the other cultivar. In areas experiencing drought, it is important to use drought-tolerance cultivars in Italian ryegrass cultivation, taking into account the genotypic differences.