The effect of genotype and culture medium on somatic embryogenesis and plant regeneration from mature embryos of fourteen apomictic cultivars of buffel grass (Cenchrus ciliaris L.)

Buffel grass (Cenchrus ciliaris L.) is an important apomictic grass used as forage for ruminant livestock. Biotechnological methods provide opportunities for producing new germplasm. Mature embryos of fourteen buffel grass apomictic cultivars (2n = 4x = 36) were used to induce embryogenic callus formation using a basal medium supplemented with 3% sucrose and with the testing of five concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and four concentrations of 6-benzylaminopurine (BAP). The effects of cultivar and culture medium on callus induction and plant regeneration were evaluated. Significant differences were observed among the fourteen cultivars and the five concentrations of 2,4-D (P < 0(.)01). Values for embryogenic callus production varied from 0 to 86(.)7. Most cultivars showed the highest level of embryogenic callus production on the medium with the concentration of 3 mg L-1 2,4-D. The addition of different BAP concentrations in combination with 2,4-D in the medium inhibited embryogenic callus growth and did not permit plant regeneration. The data clearly demonstrated that the genotype and concentrations of 2,4-D had significant effects both on the frequency of embryonic callus formation from mature embryos and on the subsequent efficiency of plant regeneration of apomictic cultivars of buffel grass. Cultivars Biloela and Nunbank showed the greatest efficiency in in vitro culture response.