Abstract
Maize is known to be susceptible to drought stress, which negatively affects vegetative growth and biomass production, as well as the formation of reproductive organs and yield parameters. In this study, 27 responsive traits of germination (G) and seedlings growth were evaluated for 40 accessions of the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) germplasm collection, under no stress and simulated drought stress treatments by 10%, 15%, and 20% of polyethylene glycol (PEG). The three treatments significantly reduced G% and retarded seedlings growth, particularly the 15% and 20% PEG treatments; these two treatments also resulted in a significant increase of abnormal seedlings (AS). The heritability (H2) and correlations of the traits were estimated, and drought tolerance indices (DTIs) were calculated for traits and accessions. The H2 of G% values were reduced, and H2 for AS% increased as the PEG stress increased. Positive correlations were found between most trait pairs, particularly shoot and root traits, with 48 highly significant correlations under no stress and 25 highly significant correlations under the 10% PEG treatments, particularly for shoot and root traits. The medium to high heritability of shoot and root seedling traits provides a sound basis for further genetic analyses. PCA analysis clearly grouped accessions with high DTIs together and the accessions with low DTIs together, indicating that the DTI indicates the stress tolerance level of maize germplasm. However, the resemblance in DTI values does not clearly reflect the origin or taxonomic assignments to subspecies and varieties of the examined accessions.
Highlights
Plants are occasionally exposed to a changing adverse biotic and/or abiotic factors, which may prevent plants from performing their maximum potential performance and can threaten their survival [1]
The G% is less affected by the 10% polyethylene glycol (PEG) treatment as compared to the 15% and 20% PEG concentrations
Evaluation of germination and seedling root, shoot and leaf traits were performed under induced osmotic stress simulated by PEG treatments as a profound base for drought tolerance of selected accessions
Summary
Plants are occasionally exposed to a changing adverse biotic and/or abiotic factors, which may prevent plants from performing their maximum potential performance and can threaten their survival [1]. Drought is a primary abiotic constraint affecting crop production worldwide, due to shortages of fresh water. Drought stress on plants occurs when the available water lags continuous plant loss of water by transpiration [2]. Global climatic change will reduce the productivity of the most valuable crops and induce a detrimental impact on the ecological fitness of cultivated crops [4]. Webber et al [5] predicted that climate change would lead to yield losses of maize and winter wheat, but drought stress would be more intensive for maize. Maintaining crop productivity for Plants 2020, 9, 565; doi:10.3390/plants9050565 www.mdpi.com/journal/plants
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