Unveiling Drought-Tolerant Corn Hybrids for Early-Season Drought Resilience using Morpho-physiological Traits

Authors: WALNE, CHARLES - Mississippi State University; THENVEETTIL, NAFLATH - Mississippi State University; RAMAMOORTHY, PURUSHOTHAMAN - Mississippi State University; BHEEMANAHALLI, RAJU - Mississippi State University; Reddy, Krishna; REDDY, RAJA - Mississippi State University

Submitted to: Plant Stress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2024
Publication Date: 3/6/2024
Citation: Walne, C.H., Thenveettil, N., Ramamoorthy, P., Bheemanahalli, R., Reddy, K.N., Reddy, R. 2024. Unveiling Drought-Tolerant Corn Hybrids for Early-Season Drought Resilience using Morpho-physiological Traits. Plant Stress. Agriculture 2024, 14, 425. https://doi.org/10.3390/agriculture14030425.
DOI: https://doi.org/10.3390/agriculture14030425

Interpretive Summary: The increasing severity of drought has become a significant threat to global crop production. Early season drought in the US Corn Belt often produces poor plant stand and grain yield. Thus, identifying corn hybrids for drought tolerance during the early season is important under drought prone conditions. Scientists from Mississippi State University, Mississippi State, Mississippi and USDA-ARS, Crop Production Systems Research Unit, Stoneville, Mississippi have assessed nineteen corn hybrids commonly grown in the Midsouthern US for drought tolerance. Plants grown under non-stress conditions were exposed to three moisture levels at 100% (control), 66% (moderate drought), and 33% (severe drought) of field capacity from V1 to V5 stage. Physiological and morphological traits of corn hybrids were measured to assess variability in drought tolerance. Shoot parameters declined by 51% and 59% under moderate and severe drought conditions, respectively, compared to the control. A decline in root traits was also noticed under drought stress (38% under moderate and 48% under severe drought) compared to the control. Total, shoot, leaf dry weights, root surface area, and root volume captured most of the phenotypic variation among the corn hybrids under drought. The results indicated that ‘A6659’ and ‘D57VP51’ as drought-tolerant hybrids during the early seedling stage. These hybrids can be used as source material in developing drought-tolerant cultivars.

Technical Abstract: The increasing severity of drought has become a significant threat to global crop production. Early season drought in the US Corn Belt often produces poor plant stand and grain yield. Thus, identifying corn hybrids for drought tolerance during the early season is important under drought conditions. Nineteen corn hybrids commonly grown in the Midsouthern US were assessed for drought tolerance using mini-hoop structures. Plants grown under non-stress conditions were exposed to three moisture levels at 100% (control), 66% (moderate drought), and 33% (severe drought) from V1 to V5 stage. Physiological and morphological traits of corn hybrids were measured to assess variability in drought tolerance. When averaged across the hybrids, shoot parameters declined by 51% and 59% under moderate and severe drought conditions, respectively, compared to the control. A decline in root traits was noticed under drought stress (38% under moderate and 48% under severe drought) compared to the control, revealing the shoot system sensitivity under drought conditions. In the principal component analysis, the first two principal components accounted for 66% of the phenotypic variation among the corn hybrids under drought stress. Total, shoot, leaf dry weights, root surface area, and root volume captured most of the phenotypic variation among the corn hybrids under drought. The results of the principal component analysis and drought stress response indices complimented the identification of ‘A6659’ and ‘D57VP51’ as drought-tolerant hybrids during the early seedling stage. These hybrids can be used as source material in developing drought-tolerant cultivars. Also, the tolerant hybrids will perform best under rainfed environments prone to early-season drought.