Callus Irradiation Is an Effective Tool for Creating New Seashore Paspalum Germplasm for Stress Tolerance

Abstract

Seashore paspalum (Paspalum vaginatum Swartz) is a perennial warm-season turfgrass which is known for its superb salinity tolerance. Compared to bermudagrass, seashore paspalum exhibited the adverse character of faster vertical growth, wider leaf, weak cold-, drought- and disease-resistance. In this study, we aimed to improve these unfavorable traits of seashore paspalum through the strategy of callus irradiation. The results showed that 2108 regenerated plants were obtained following the method of the seashore paspalum calluses irradiated by 60Co-γ rays (dose: 60 Gy, dose rate: 1 Gy/min). Morphological traits were measured combining with cluster analysis on the regenerated plants to select mutant lines with short leaves (A24 and A82) and thin leaves (A24, A83, and A120) as well as dwarfism (B73, B28, B3, A29, and B74). In addition, we found various mutant characters such as greenish leaf sheath (A69 and A71), soft leaf (B77, B17, and B110), and strong erectness (B5 and B9) under continuous observation. Through the comprehensive tolerance analysis following the index of survive rate, relative water content, leaf electrolyte leakage, MDA content; photochemical efficiency and leaf wilting coefficient, three drought-tolerant lines (A55, B72, and B44) and one cold-tolerant line (B59) were screened. This research proved that callus irradiation is an effective way to create new seashore paspalum germplasm, which provides valuable materials for accelerating the breeding process of seashore paspalum and further excavating the molecular regulatory mechanisms of these traits in turfgrass.