Somatic Embryogenesis in Bluestem Grasses (Bothriochloa Species)

Abstract

A group of grasses commonly known as Old World bluestems, represented by three genera (Bothriochloa, Dichanthium and Capillipedium), belong to the generic section Bothriochloininae of the tribe Andropogoneae (Chheda and Harlan 1962). The genus Bothriochloa, native to Europe and Asia (Harlan 1963) was first introduced into the United States in 1914 (C. Dewald, pers. comm.). Three species of the genus Bothriochloa, namely, B. caucasica, B. intermedia, and B. ischaemum, have been widely cultivated for forage in the southern Great Plains of the USA, as they are well adapted to the warm season and different soil conditions in this region (Sims and Dewald 1982). These grasses exhibit an apomictic mode of reproduction (Taliaferro et al. 1989). Seeds of an apomict contain embryos that are produced asexually from the maternal tissue (Nogler 1984). Improvement of an apomictic species through conventional breeding is very difficult, because it cannot be used as a female parent to produce a hybrid. The development of efficient in vitro regeneration protocols may allow the use of biotechnological techniques for the improvement of these crop species. In our laboratory, a tissue culture method to regenerate plants via somatic embryogenesis was developed as an initial step in attempts to improve nutritional qualities and biomass production in caucasian bluestem [Bothriochloa caucasica (Trin.) C.E. Hubbard].