ABSTRACT
Cultivated plants are propagated whenever possible by seeds as a convenient means of multiplication, storage, and distribution. Seeds are an ideal propagation system. As a definition, artificial seeds may be considered as somatic embryos engineered to be of use in commercial plant propagation. Zygotic embryo formation begins with the double fertilization of the egg and polar nuclei, whereas somatic embryos are formed by the differentiation of somatic cells. The report of somatic embryogenesis in alfalfa has been followed by many reports of regeneration from callus, suspension, and protoplast cultures. The suspension culture phase disperses the proembryonic cells and induces the formation of new embryogenic cell clusters. Genetic transformation of alfalfa using Agrobacterium vectors has been accomplished with the objective of introducing useful traits including herbicide resistance and environmental stress tolerance. A "hybrid" alfalfa cultivar would maximize genetic heterozygosity and therefore agronomic performance.
