Tissue culture-induced morphological somaclonal variation in St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze]

Somaclonal variation has been observed in many plant species and is an alternative way to create variants and expand the germplasm pool. A large scale tissue culture experiment was conducted with St. Augustinegrass, an important turfgrass species for the southern USA, to induce somaclonal variation to enlarge the germplasm pool for breeding efforts. Using an improved protocol, approximately 7900 St. Augustinegrass plants were regenerated from cv. 'Raleigh', and 119 morphological variants were identified. Among the variants, 115 had a semi-dwarf growth habit with shorter and narrower leaves, and shortened internodes and stolons. However, 100 of them showed little vigour, which either grew very slowly or did not survive. The remaining 15 showed reasonable growth vigour and were further investigated in the field. Among them, 13 were semi-dwarf and 2 had longer leaves. In addition, 2 other variants, with variegated (yellow striping) leaves, or significantly thicker stems were also observed and characterized. The altered traits in the variant lines were stable during vegetative propagation and when grown in different environments.