IMPORTANCE OF ACREMONIUM ENDOPHYTES IN TURF-GRASS BREEDING AND MANAGEMENT

The development and use of genetically improved turf-grasses containing useful endophytes is of great value in efforts to enhance the environment, reduce maintenance costs, and conserve and improve precious soil and water resources. Acremonium endophyte-infected (E+) turf-grasses have frequently shown dramatic enhancement of resistance to many foliage-feeding insect pests. Modest improvements in resistance to root-feeding white grubs and some nematodes have been reported. Improvements in stress tolerance and modifications in water relations have been observed under certain conditions. Acremonium endophytes cause modifications to physiological mechanisms of adaptation of the host that result in superior performance of some turf-grass genotypes during moisture deficits. An understanding of the role of endophytes in modifying host plant performance makes turf-grass breeding and evaluation much more efficient. During 1990, an estimated 6000 tonnes of seed of elite, E+ containing perennial ryegrasses, Lolium perenne L., was produced and utilized throughout the world. Endophyte-enhanced ryegrass cultivars include 'Advent', 'Assure', 'Dandy', 'Dasher II', 'Gettysburg', 'Pinnacle', 'Repell', 'SR 4200', 'Seville', and 'Sherwood'. Acremonium endophytes have been incorporated into 'Reliant' and 'SR 3000' hard fescue, Festuca longifolia Thuill, 'SR 5000' and 'Jamestown II' Chewings fescue, Festuca rubra L. subsp. commutata Gaud., as well as elite germplasm of these species. Lower-growing, turf-type tall fescues, Festuca arundinacea Schreb., are being developed with high infection levels of useful Acremonium endophytes. Efforts are being made to find or develop and use desirable endophytes in Kentucky bluegrass, Poa pratensis L., strong creeping red fescue, F. rubra L. subsp. rubra, blue fescue, Festuca glauca Lam., and various bentgrasses, Agrostis spp. The discovery and/or development of superior genetic strains of Acremonium endophytes will make endophyte-enhanced turf-grass performance of even greater significance. There is also the potential to discover, genetically modify, and use other species of fungal and bacterial endophytes with the ability to improve turf-grass performance.