Evaluation of South African Bermudagrass Germplasm for Shade Tolerance.

Bermudagrass, Cynodonspp., is one of the most commonly grown turfgrass genera in North Carolina. The grass is extremely drought tolerant which makes it a very desirable species especially under new demands for water allocation. However, bermudagrass lacks shade tolerance, a valuable trait for use in smaller residential landscapes where trees are dominant, as is the case in many neighborhoods in North Carolina.  Development of cultivars with shade tolerance would allow bermudagrass to become more prevalent in home lawns. In this study, a set of nine bermudagrass accessions collected from shaded areas in the Pretoria region of South Africa were evaluated for their ability to perform well under low light conditions. These materials, along with three standard cultivars (Celebration, TifGrand and Tifway) were evaluated under three levels of shade (0%, 63%, and 80%) at two locations (Raleigh and Jackson Springs, NC), during two growing seasons (2011-2012). The experimental design was a split-split plot where the main plot factor was percent shade, the subplot factor was genotype and the sub-sub plot factor was fertility level. The variables measured were recovery under shade and turf quality. For both years, significant differences among shade levels, genotypes, and the interaction of the two were observed. The progression from 0% to 63% to 80% shade severely reduced the recovery and turf quality of all accessions, as expected; however, some genotypes were able to maintain aggressiveness under these less than optimal conditions. Results from Raleigh, indicated that Celebration, WIN10F, and STIL03 were significantly better than Tifway, the susceptible control. Furthermore, recovery of WIN10F was not compromised by an increase in shade from 63% to 80%. Overall, our results indicate that there are promising genotypes among the bermudagrass materials collected from South Africa. These materials might provide additional sources of shade tolerance to be used in bermudagrass breeding with the goal of releasing cultivars that are able to grow well and maintain good quality under low irradiance.