Evaluation of University of Georgia Turfgrass Germplasm for Response to Sting Nematode Feeding.

Turfgrasses grown in the sandy, well-drained soils of the Atlantic coastal plain in the United States will likely encounter sting nematode (Belonolaimus longicaudatus) pressure.  The identification of resistance or tolerance genes which would allow new cultivars to thrive in plant-parasitic nematode infested soils would greatly serve the turfgrass industry.  Therefore, an experiment to determine the response of differing turfgrass genotypes to sting nematode feeding was conducted during the 2009 growing season and repeated in 2011 in a glasshouse at the University of Georgia Tifton Campus.  ‘TifSport’ and ‘TifGrand’ bermudagrasses (Cynodon dactylon × C. transvaalensis), the two parents of a bermudagrass mapping population, T89 (C. dactylon) and T574 (C. transvaalensis), used to create a linkage map at the University of Georgia, and two seashore paspalum (Paspalum vaginatum) genotypes, ‘SeaIsle1’ and UGA 31, were established from nematode-free, aerial stolons and inoculated with 50 sting nematodes.  Significant differences were detected for final sting nematode population density among these six turfgrasses, but reproduction factors indicate that resistance is not present.  The latest University of Georgia releases, TifGrand and UGA 31, exhibited greater total root length under sting nematode feeding as compared to their respective industry standards, TifSport and SeaIsle1.  This suggests that maintenance of longer roots is possible when these genotypes are subjected to sting nematode feeding.  Equally as promising was the discovery that the parents of our bermudagrass mapping population varied greatly in their susceptibility to the sting nematode during 2009 as indicated by the differential response in percent reduction of total root length.  This study provides a preliminary view into the responses of six turfgrass genotypes when subjected to the sting nematode.  Work should continue to further test the field resistance and tolerance of all evaluated turfgrasses in research conducted outside of the controlled greenhouse environment.