Tall fescue breeding can be divided into several periods. Before 1981, breeders were not aware of the importance or implications of the endophyte to tall fescue. The period of 1981 to 1995 saw an explosion in knowledge regarding the endophyte, the widespread use of E- cultivars for forage planting, and a rapid expansion in the supply and demand for improved tall fescue turf cultivars (Table 19-4). Pedersen and Sleper (1988) reviewed the changes brought about in tall fescue forage cultivar development resulting from knowledge of the endophyte. Important changes impacting cultivar development from 1996 to 2005 included strengthening of the Plant Variety Protection Act in the United States and the advent and early application of novel, nontoxic endophytes.
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As indicated by cultivar registrations in Crop Science, virtually all tall fescue turf cultivars developed after 1980 were derived directly from advanced breeding populations as a result of recurrent selection (Table 19-5). These advanced breeding lines in turn trace back almost exclusively to ecotypes collected from old turfs in the eastern, southern, and central United States, primarily by the turf breeding program at Rutgers University. Cultivars have become the major source of base germplasm for developing advanced breeding lines and subsequently improved commercial varieties, particularly after the early 1990s. The closely related cultivars Rebel and Olympic were specifically listed in the pedigree of 44 and 8%, respectively, of all turf cultivars registered between 1981 and 2005. Some cultivars, such as Olympic Gold (Fraser et al., 2001) and Grasslands Garland (Rumball et al., 1991), were selected almost exclusively from germplasm closely or directly related to Rebel. Likewise, the forage cultivars Mozark, Penngrazer, Phyter, and Stargrazer were selected in part or entirely out of KY-31 (Alderson, and Sharp, 1994).
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Table 19-5. Trends in tall fescue breeding as indicated by turf cultivars registered by the American Society of Agronomy or the Crop Science Society of America, 1945 through 2005. Period indicates date of registration. Percentage germplasm contribution and trait selection derived from descriptions in registration articles. Percentages may total more than 100 because of rounding.
We suspect that within the next 5 yr tall fescue breeding will enter a new era with the application of biotechnologies such as genomics and marker-assisted selection (see Chapter 21). However, we speculate that tall fescue cultivars or accompanying endophytes incorporating transgenic technology will not reach the marketplace within the next several years. In the United States and elsewhere, the challenges of strict and expensive regulatory processes pose a prohibitive barrier for marketing transgenic tall fescue cultivars in the immediate future.
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