348 In Vitro Establishment and Growth of Bermudagrass, Buffalograss, Saltgrass, and Zoysiagrass
There are turfgrasses species that are clonally propagated; notably bermudagrass, buffalograss, and zoysiagrass. Some of the early cultivars of these species are no longer widely grown, and may eventually be lost if not preserved. In order to facilitate studies on the long-term cryopreservation of these species and specific lines of saltgrass, it is necessary to develop suitable micropropagation procedures. We have developed protocol for the isolation and establishment of clean cultures in vitro for all four species. A 1/2-strength MS basal medium with Nitsch & Nitsch vitamins, 5 mg/L of thiamine, 2 mg/L of glycine, 30 g of sucrose, 7 g of agar with varying growth regulators has been used. Explant materials are prewashed in the greenhouse prior to a 15- to 30-min soapy wash in the laboratory. After a 30- to 60-min rinse in running water, nodal sections are surface-disinfested in 10% bleach with Tween 20 for 15 min, followed by three sterile water rinses. This procedure, sometimes with PPM (a proprietary antimicrobial compound), results in 50% or greater clean cultures. Rapidly growing nodal sections work best and preferably those not established in soil. We have tested various growth regulator combinations and have found that 10 mg/L of BA results in proliferation of buffalograss and saltgrass. However, proliferation remains relatively slow, requiring 8 to 12 weeks to develop sufficiently for subculture. Although we have succeeded in obtaining clean cultures of bermudagrass and zoysiagrass, proliferation is minimal, Further research is ongoing to develop a proliferative system with these two species.