Assessing drought resistance in seashore paspalum genotypes using leaf gas exchange, osmotic adjustment, and rooting characteristics

The objective of this study was to compare drought resistance in a range of seashore paspalum (Paspalum vaginatum Sw.) genotypes and identify associated morphological and physiological traits. Fifteen genotypes were grown in growth chamber conditions and exposed to well-watered and drought-stress treatments. Genotypes 'Seaisle1' and PI647891 were consistent top performers, whereas 'Seastar' and PI614680 performed poorly as measured by turf quality, percentage green cover, and relative water content when exposed to drought stress. Observed levels of drought resistance had no significant relation with morphological traits such as leaf width and internode length but were found to be associated with various physiological traits. Drought resistant genotypes were able to better maintain membrane stability, photosynthesis, and had greater water use efficiency compared with sensitive genotypes. Earlier osmotic adjustment at 7 d via faster osmolyte accumulation was a significant contributor to performance during drought. Drought-resistant Seaisle1 and PI647891 had deeper roots and greater root length density than drought sensitive 'Seastar' and PI614680. Results showing variability in the level of drought resistance and associated mechanisms in understudied seashore paspalum genotypes could facilitate future breeding efforts for developing drought-resistant turfgrass cultivars.