PERFORMANCE OF BUFFELGRASS GERMPLASM WITH IMPROVED WINTER SURVIVAL

Lack of winter hardiness in buffelgrass [Cenchrus ciliaris L.; syn. Pe nnisetum ciliare (L.) Link] currently limits the utilization of this s pecies in Texas and northern Mexico. This study was conducted to asses s differences in field survival and yield potential of buffelgrass ger mplasm believed to have increased levels of winter hardiness. To docum ent differences in held winter survival seedlings of five buffelgrass genotypes ('Common', 'Llano', 'Nueces', PI 409704, and T-7040) were es tablished at six locations in Texas ranging from 28 to 34 degrees N la titude. The winter-hardy species Pennisetum orientale L. cv. Cowboy wa s included as a check. The buffelgrass entries PI 409704 and T-7040 (a 2n + n hybrid between 409704 and an unknown male parent) had greater field survival than the cultivars Common, Llano, and Nueces, but were less winter hardy than Cowboy at the three locations (Knox City, Steph enville, and Vernon) north of College Station. All entries survived th e winter at Beeville, College Station, and Uvalde. Yield at two cuttin g heights was evaluated over a 3-yr period at College Station. The rhi zomatous cultivars Llano and Nueces had the greatest yield when harves ted at 50 mm, while no significant differences existed among Llano, Nu eces, PI 409704, and T-7040 when harvested at 150 mm. Defoliation heig ht influenced winter survival of Common buffelgrass at College Station . During the winter of 1987-1988, 60 and 20% of the Common plants fail ed to survive at the 50- and 150-mm defoliation heights, respectively. Defoliation height did not affect crown nonstructural carbohydrate co ncentration (CHO). The most winter-hardy entry, Cowboy, had the highes t CHO; the least winter-hardy entry, Common, had the lowest. These res ults suggest that winter-hardy pentaploid buffelgrass germplasm such a s PI 409704 have the potential to expand the current range of buffelgr ass.