Morpho-physiological Responses of Sorghum Cultivars to Drought Stress

The experiment was carried out to assess the following objectives: (i) To understand the effect of drought stress on plant height and leaf area in diverse sorghum genotypes. (ii) To study the alterations in chlorophyll index and yield components under drought stress. (iii) To correlate yield with all morpho-physiological traits to understand drought tolerance mechanism of sorghum. Screening experiment was carried out in Augmented design I during April 2022 to July 2022 at Rain Out Shelter (ROS), Department of Crop Physiology, Tamil Nadu Agricultural University, Coimbatore. 33 germplasms from Agricultural Research Station, Kovilpatti (ARS, Kovilpatti) and Indian Council of Agricultural Research- Indian Institute of Millet Research, Hyderabad (ICAR-IIMR, Hyderabad) were collected. Among 33, M35-1, K -12, CSV 27 and CSV 29-R were used as checks, where all the germplasms were cultivated with two treatments under field conditions; T1: (Control) well watered throughout life cycle, T2: Two weeks of drought stress (50%) at booting stage. Traits such as plant height and leaf area, were recorded before and after imposing drought. Chlorophyll index, ear head weight, ear head length, grain yield, total dry matter production, harvest index were recorded after imposing drought stress in control and drought stress. Under drought stress morpho-physiological and yield traits significantly reduced compared to control. There was a significant positive correlation of yield under stress with all the morpho-physiological traits. Among ICAR-IIMR sorghum germplasm collections screened for drought stress tolerance PEC 14, PEC 17, PEC31, PEC 34 EP 90 showed drought tolerance on par with the checks. Similarly, TKSV 1036, TKSV 1707, TKSV 1801, TKSV 1802 germplasms from ARS, Kovilpatti were tolerant to drought stress at booting stage.