NE1010: Breeding and Genetics of Forage Crops to Improve Productivity, Quality, and Industrial Uses
Statement of Issues and Justification
The economics of farming continues to be one of the major agricultural problems in the U.S. One important component of the solution is to increase profitability by crop improvement through plant breeding. Improved forage cultivars provide economic opportunities for livestock and crop farming operations and promote a more stable, sustainable agriculture. Farmers benefit by greater animal product per unit of land or forage produced, and the consumer benefits by maintenance of low cost food. Improved seed production capacity also ensures a satisfactory product for seed producers and a low seed price to the forage grower. All Americans benefit as genetic improvement is the least costly and most stable way to maintain international agricultural competitiveness, decrease the amount of land lost to agricultural production, and protect the environment by decreasing the use of pesticides, herbicides, and fertilizers.Multistate cooperative research by NE-144 impacts directly upon all five national goals of the "Agricultural Research, Extension, and Education Reform Act of 1998." These goals are: (1) an agricultural system that is highly competitive in the global economy, (2) a safe and secure food and fiber system, (3) a healthy, well-nourished population, (4) an agricultural system which protects natural resources and the environment, and (5) enhanced economic opportunity and quality of life for Americans. What follows is a description of the problems, the general role of forage species in helping to solve these problems, and the specific role of forage breeders in researching these problem areas.
Forage crops constitute the foundation of livestock and dairy enterprises in the U.S. and Canada while also serving vital environmental functions. In order for livestock farms to be profitable, for environmental goals of reduced pollution and sustainability to be met, and for consumers to have meat and milk products available at low prices, forage cultivars with improved persistence, quality, and productivity need to be developed. As budget reductions have resulted in fewer forage breeding positions, the need for cooperative research to develop germplasm and cultivars with new traits is essential. The paucity of forage breeding belies the value of forage crops: measured solely as the value of hay, forages rank 4th behind corn, soybean, and wheat in cash receipts among all U.S. field crops. Yet, the combined number of scientist-years (SY) devoted to forage breeding at all state agriculture experiment stations is fewer than one for each species, with the exception of alfalfa, which had 15 SY's in 1994. For comparison, corn, soybean, and wheat had 32, 45, and 65 SY's respectively. Furthermore, half of all US plant breeding efforts, public and private, are devoted to corn, soybean, cotton, and wheat. Among all forage crops, only a few (alfalfa, perennial ryegrass) receive any investment from private breeding companies. Those companies are disappointed that public institutions do not devote enough research on new traits and on forage species that companies do not breed.
Furthermore, all perennial forage species must be broadly adapted to market the volume of seed required to justify its production and marketing. Evaluation of genotypes, germplasm, and new cultivars must be done at multiple locations. A system currently is in place to accomplish this extensive evaluation among NE-144 cooperators. In addition, m,olecular marker systems have shown their potential usefulness for forage improvement, but prohibitive costs prevent all breeders from having laboratory facilities. The current NE-144 committee fosters the interactions necessary to accomplish more breeding with diminishing resources without unnecessary duplication of breeding efforts. Thus, enhancing our knowledge of forage crop breeding and genetics and developing improved germplasm and cultivars can only be done through collaboration among public scientists.
Plant breeders can improve pest resistance, persistence, and quality of forage crops without reducing forage yield potential (Anderson et al., 1988; Eichorn et al., 1986). These improvements can be made without passing increased seed costs to the farmer and without the need for increased management or input costs (Vogel et al., 1981). Thus, the farmer benefits by producing more animal product per unit of land or forage, and the consumer benefits through low cost food. Improved seed production capacity, or even maintenance at accepted levels, also ensures a satisfactory profit for seed producers and an acceptable seed price to forage growers.
The cooperative research with new traits, breeding methodologies, and molecular markers ultimately will result in new germplasms and cultivars that will enhance more economical production of forages and production of livestock products. Therefore, we will help foster a more diversified agricultural system that relies less on commodity grain production and improves agricultural sustainability.
Agriculture is the largest nonpoint source of water pollution in the U.S., accounting for 50% of all water pollution (Chesters and Schierow, 1985; Myers et al., 1985). Agricultural runoff carries nutrients, pesticides, and sediment into surface waters. Approximately 20% of U.S. cropland is subject to serious damage by erosion (Clark et al., 1985; USDA, 1987a and 1987b). Perennial forage crops are the most effective source of cropland vegetation in reducing water runoff and topsoil removal (Reganold et al., 1987; Wadleigh et al., 1974; Wischmeier and Smith, 1978). Their high level of ground cover and extensive root systems reduce soil erosion, increase water percolation, and reduce nutrient loading of both surface and ground water. Their perenniality also reduces the frequency of heavy tillage operations required in crop rotations. Reducing frequency of tillage reduces runoff and pesticide loading of surface waters (Glenn and Angle, 1987). In addition, tilled fields without cover crops are more susceptible to erosion and leaching of applied chemicals than are fields with a high level of ground cover (Hoyt and Hargrove, 1986; Reganold et al., 1987). A reduction in the use of forage crops has made control of soil erosion difficult in some regions (NRC, 1989).
Legume-based crop rotations can sustain high levels of grain production without the use of nitrogen fertilizer (Power, 1987). Legume cultivars with greater persistence, N2 fixing ability, disease and insect resistance, and greater resistance to environmental stresses will be extremely useful in the development and implementation of environmentally sound crop production systems.
Changes in crop production strategies toward reduced nitrogen fertilization and greater use of forage mixtures, will require changes in breeding strategies for continued development of improved cultivars and germplasm. Development of superior perennial grass cultivars for use in low applied nitrogen crop production systems will require breeding efforts under similar conditions. In perennial grasses, cultivars with the highest yield and quality under high nitrogen rates are not always the cultivars with the best performance under low nitrogen rates (Vose, 1963). Different nitrogen levels can also cause different genotypes to be selected from breeding nurseries. Grasses adapted to use in grass-legume mixtures may be more productive and stable than in monocultures (Chamblee and Collins, 1988) and have fewer weed problems (Drolsom and Smith, 1976). Breeding and testing under monoculture conditions does not allow selection of genotypes or cultivars with maximum performance in mixtures (Casler and Drolsom, 1984).
Cool-season forage species are extremely versatile with broad collective adaptation to virtually any cultivated lands in the northern U.S. and Canada. Therefore, they are often relegated to poorer soils and sites less conducive to row-crop production, such as waterlogged soils, hard pans, droughty sites, etc. Species such as alfalfa are highly productive on good soils but have severe production problems on heavy, wet, or acid soils. Other forage species are well adapted to each of these conditions and provide excellent alternatives under those circumstances. In addition, selection procedures can be used to genetically modify species for adaptation to stressful soil conditions (Charles, 1972; Snaydon, 1978). Breeding cool-season forage crops for resistance or tolerance to various environmental and biological stresses is an important component of research designed to maximize the efficiency of animal production on various types of marginal lands. Unfortunately, little support for these breeding programs exists outside of publicly funded institutions.
The use of pastures is widely practiced in the northern U.S. and Canada. It is an alternative means of producing high quality feed without the need for input costs associated with harvesting, processing, and storing cured feeds. Technological advances of the mid-20th century and the results of dairy production experiments (Larsen and Johannes, 1965) led to the widespread practice of hay and silage production from forage crops. Forage breeders, in their attempts to provide the best products for accepted management systems, followed this trend. Forage crop cultivars well adapted to hay and silage management systems tend to be more upright in growth habit, less densely-tillering, and earlier in maturity than those adapted to pasture systems (Stapledon, 1928). Consequently, cool-season forage crop cultivars are relatively unadapted to the frequent, intensive, rotational grazing systems (Voisin, 1988) now being adopted by many farmers.
Collaborative regional research is an essential component of an effective North American forage breeding research and cultivar development system. Forage breeders are trained at widely divergent institutions, which have differing specialties, resources, and philosophies. Most breeders have a secondary area of specialization, typically plant pathology, entomology, plant physiology, biometry, quantitative genetics, molecular genetics, or cytogenetics. Collaboration on specific shared objectives is an efficient means of combining resources and expertise into important researchable objectives.
Forage breeding programs are unique in that nearly all forage breeding/genetics project leaders conduct research on multiple species. Although individual effort is small for some forage species, the cumulative impact from cooperative efforts among forage breeders is significant. Due to diversity among forage production environments and livestock production systems, farmers in any state or province collectively use a large number of species to meet their forage needs. No single breeder can conduct a research/cultivar development program on all species of economic importance. Furthermore, there are no public forage breeding programs in many important forage producing regions of the Northeast and Northcentral U.S., and few private companies actively breed perennial forages. As a consequence of these factors, relatively little effort is placed on some species for which important researchable goals remain unmet.
The members of the NE-144 Multistate Research Committee represent nearly all public efforts aimed at cool-season forage breeding in the humid, temperate portions of the U.S. and eastern Canada. The exceptions are a few alfalfa breeders and geneticists. Thus, research efforts described in this document do not represent duplication of any efforts underway in other institutions of the U.S. or Canada. A recent search of the CRIS system has further verified the validity of this conclusion.
Because of the long-term nature of research on perennial forage species, many of the collaborative efforts begun during the last NE-144 five-year period will continue into the next. In addition, completion of some efforts has led to new research projects that justify continued collaborative research in the proposed 15-year period. Furthermore, the high degree of collaboration among the NE-144 scientists will no doubt foster the initiation of additional collaborative efforts not yet envisioned.
Funding for these collaborative efforts will be only partially covered through the NE-144 project. Scientists currently supplement these cooperative research efforts with funding from other sources, such as from seed industry, royalties from seed of cultivars, and various sources of public funding (state and federal) for molecular and other types of research. USDA and Ag Canada participants fund their efforts from federal sources as well as from competitive grants. In addition, we anticipate that NE-144 funding will serve as seed or matching funds leading to more opportunities for research funding from other sources, as it has in the past.
Back to Top