Researcher(s)
- Phoebe Baker, Agriculture and Natural Resources, University of Delaware
Faculty Mentor(s)
- Dr. Qi Mu, PLSC, University of Delaware
Abstract
Climate change is expected to accelerate agricultural soil salinization through sea-level rise and saltwater inundation, increased drought and saltwater intrusion, altered precipitation patterns, and increased evapotranspiration. These processes threaten crop productivity, flooding the root zone with toxic sodium, competing with other ion channels where plants utilize essential nutrients. Active pumps used to transport sodium are hindered by excessive salinity and waterlogging, frequently occurring together. Salinity-affected areas are seen in low-lying regions where flooding would have also occurred. Therefore, elucidating the phenotypes of maize to these stresses is instrumental for genetic studies.
Many commercial genotypes, including B73, have been evaluated for responses to these stresses individually, but not simultaneously. Does W22 react better or worse than B73 in waterlogged and/or saline conditions, and which treatment is most destructive?
Replicates were grown in controlled conditions with salinity, waterlogged, salinity and waterlogged, and control treatments. NaCl was dissolved in water until EC of 10 dS/m was reached, then applied through irrigation. Treatments were imposed at V3 and phenotyping was done 7 days post-treatment. One plant from each treatment was phenotyped for recovery after growing 7 days in normal conditions.
The combined salinity and waterlogging treatment was worse across all treatments. W22 had higher reductions in number of leaves, leaf width, shoot height, root length, shoot/root weight, and adventitious roots, and higher ratings for root rot.
There were several genotype-dependent interactions between treatments. B73 maintained high lateral root ratings under salinity, with a reduction under waterlogging and combined stress. W22 had more lateral roots under waterlogging, with a severe reduction under combined stress. W22 also produced more adventitious roots in waterlogging and less in salinity and waterlogging, while B73 had an inverse relationship.
This study will help formulate new hypotheses about whether waterlogging and salinity tolerance are linked or independent traits.