Alfalfa

Cultivated alfalfa or lucerne (Medicago sativa spp. sativa) is the most important forage legume in the world with approximately 32 million hectares cultivated mainly in the temperate regions of both the northern and southern hemispheres. Intensive research has been conducted on the management and physiology of the crop and a major seed industry has developed world wide. Since insect and disease pests are numerous in alfalfa, development of cultivars with the proper fall dormancy and a broad genetic base for pest resistance has been pursued in order to provide increased adaptation, persistence, and yield. There has been a movement lately to introduce more complex genetic traits into these multiple pest, dormancy specific cultivars. Cultivars with grazing tolerance, potato leafhopper resistance (achieved via introgression of genes for glandular hairs from related Medicago subspecies), and low bloat incidence are now marketed. Continued alfalfa breeding will be necessary to develop resistance to intransigent pests such as Lygus, expand adaption into hostile environments such as saline or acid, aluminum toxic soils, incorporate true bloat resistance, increase N2 fixation, and maximize economic yield. The use of biotechnology methods to improve the crop has already begun. Molecular markers are now being assessed for their practical use in alfalfa breeding. The introduction of novel genes via transformation is also underway in alfalfa. In addition to its role as the major legume hay, silage, and pasture crop, alfalfa is currently being investigated as a fuel for use in generating electricity, a bioremediaton system for removal of harmful nitrates, a source of pulp for paper manufacturing, and a factory for production of industrial enzymes. Finally, alfalfa’s future use as a component in low management mixed pastures, in sustainable conservation agriculture, or as a viable crop in the tropics is beginning to be examined