Screening of lentil genotypes during germination and early growth stages under PEG-induced drought stress

Abstract

The objective of this experiment was to determine drought tolerance exhibited by lentil lines developed by the International Center for Agricultural Research in the Dry Areas (ICARDA) in an artificial environment, and to investigate the relationships between traits with various methods. This experiment examined 15 traits of 21 lentil (Lens culinaris Medik.) accessions grown under artificial drought stress created with polyethylene glycol (PEG)-6000 (0%, 10%, 15% and 20%) concentrations during germination and early seedling stages. Germination characteristics, seedling developmental properties and root system architecture traits were investigated to observed the impacts of drought stress. The originality lies in enabling the identification of drought-tolerant and sensitive genotypes through a brief and practical research method, while shedding light on the key traits by principal component analysis. The first two PCs explained 22.9% and 31.7% (total 54.6%) under optimal conditions while they described 14% and 58.3% (total 72.3%) under PEG-induced drought conditions, respectively. Variation in PC1 was mostly contributed by positive coefficients of germination index, uniformity of germination and germination energy, and negative coefficients of mean germination time. Variation in PC2 was mostly contributed by positive coefficients of seedling vigor index, root fresh weight and root dry weight. 'Tigris', G3664 and G3840 exhibited higher performance in terms of germination characteristics, while G3710, G3829 and G3840 produced higher DM accumulation, total biomass and lateral roots. Overall, PC-biplot denoted that selection based on germination index and seedling vigor index at germination and seedling stages would improve drought tolerance. In conclusion, genotypes G3840 and G3664 were identified as drought-tolerant, whereas genotypes G35, G3659, G3759, G3837, and G3844 were classified as drought-sensitive. In addition, G3664, G3840 and G3710 exhibited the highest stress tolerance index (STI) under artificial drought conditions.