Phenotyping sorghum for drought-adaptive physiological and root architectural traits under water-limited environments

Drought is one of the most important abiotic stresses that adversely affect plant growth and productivity. Drought regulates a multitude of biochemical and physiological processes in plant system. It is necessary to understand the traits associated for identifying drought-resilient sorghum lines. A field experiment was conducted with 20 rabi sorghum genotypes to study the variation in physiological and key root traits that contribute the drought tolerance under irrigated and stress conditions. Genotypes, Phule Anuradha and RSV 2145 recorded early flowering (68 and 69 days, respectively) under the stress condition, while both STG 25 and RSV 2145 recorded 108 days for physiological maturity. Genotype RV 48 recorded significantly higher leaf area (1355 cm(2)) and leaf area index (2.01) than check M 35-1 (1288 cm(2) and 1.90, respectively) under the stress condition. The maximum relative leaf water status was recorded in M 35-1 (84.40%) under the stress condition, an indicator of wider adaptability. Genotypes CRS 67 and STG 44 recorded higher root length (56 cm and 55 cm, respectively) compared to check M 35-1 (40.67 cm) under the stress condition reflecting that root length helps in absorption of water from deep ground level. Root volume was significantly higher in Phule Suchitra and STG 21 (7.56 cm(3) and 6.30 cm(3), respectively) under the stress condition. The root dry matter was more in Phule Suchitra (8.83 g) followed by CRS 67 (7.73 g) and M-35-1 (5.03 g) under the irrigated condition. Under stress, M 35-1 recorded significantly higher root biomass (4.06 g) followed by STG 44 (3.78 g). The grain yield was maximum in Phule Suchitra (80.00 g) followed by Phule Anuradha (64.00 g) under the stress condition. The experiment concluded that the root traits indicate the adaptability of the genotypes for drought condition, and CRS 67, Phule Suchitra and STG 44 with higher root traits can further be used in the breeding programs for drought tolerance. Collectively, these results demonstrate that the role of physiological traits and root architecture development are key factors in understanding the interplay of drought stress.

Automated summary

This study investigated the variation in physiological and root traits of 20 sorghum genotypes under irrigated and stress conditions. The results showed that genotypes with higher root traits, such as CRS 67, Phule Suchitra, and STG 44, exhibited increased drought tolerance. Root traits play a key role in understanding the impact of drought stress on plant growth and productivity.