Tissue culture and plant regeneration of blue grama grass, Bouteloua gracilis (HBK) Lag. ex Steud.

As a first step towards applying biotechnology to blue grama, Bouteloua gra cilis (H.B.K.) Lag. ex Steud., we have developed a regenerable tissue cultu re system for this grass. Shoot apices were isolated from 3-d-old seedlings and cultured in 15 different growth regulator formulations combining 2,4-d ichlorophenoxyacetic acid (2,4-D), Picloram (4-amino-3,5,6-trichloropicolin ic acid), N-6-benzyladenine (BA) or adenine (6-aminopurine). The highest in duction of organogenic callus was obtained with formulations containing 1 m g l(-1) (4.52 muM) 2,4-D plus 0.5 mg l(-1) (2.22 muM) BA, and 2 mg l(-1) (8 .88 muM) BA plus 1 mg l(-1) (4.14 muM) Picloram with or without 40 mg l(-1) (296.08 muM) adenine. Lower frequencies of induction were obtained for emb ryogenic as compared to organogenic callus. The most efficient treatments f or induction of embryogenic callus contained 2 mg l(-1) (9.05 muM 2,4-D com bined with 0.25 (1.11 muM) or 0.50 mg l(-1) (2.22 muM) BA, or 1 mg l(-1) (4 .52 muM) 2,4-D with 0.50 mg l(-1) (2.22 muM) BA. Regeneration was achieved in hormone-free Murashige anmd Skoog (MS) medium, half-strength MS medium o r MS medium plus 1 mg l(-1) (1.44 muM) gibberellic acid. The number of plan tlets regenerated per 500 mg callus fresh weight on MS medium ranged from 9 for 2 mg l(-1) (9.05 muM) 2,4-D to 62.2 for induction medium containing 2 mg l(-1) (8.28 muM) Picloram, 1 mg l(-1) (4.44 muM) BA and 40 mg l(-1) (296 .08 muM) adenine. Regenerated plants grown in soil under greenhouse conditi ons reached maturity and produced seeds.