GENOTYPE EFFECTS ON PLANT-REGENERATION IN CALLUS AND SUSPENSION-CULTURES OF AVENA

Regenerative potential of the calli of nineteen genotypes of Avena sativa, Avena nuda, Avena byzantina and one interspecific hybrid were compared over three successive cultures. Highly significant genotype and genotype x subculture interactions were observed. Among the highest plant regenerable genotypes were 'Corbit' (first subculture); 'GAF/Park' and '88Ab3073' (second subculture); and 'GAF/Park' and '87Ab5932' (third subculture). These genotypes regenerated on an average 10 to 17 plants each from a 200 mg callus mass after a 30 to 45 proliferation period. 'GAF/Park', a progeny of an interspecific cross, regenerated plants at a significantly higher level (11.85 plants/rep), followed by the similarly performing A. sativa (6.23 plants) and A. nuda (5.06 plants) genotypes, which were significantly higher than the A. byzantina genotypes (2.07 plants). Four genotypes were tested for their adaptability to suspension culture and plant regeneration potential by separating their cells and cell clusters into two sizes: larger and smaller than 3 mm. Larger clusters yielded plants for three genotypes 'GAF/Park', '88Ab3073', and 'Tibor'. The smaller clusters only regenerated plants for 'GAF/Park' and '88Ab3073'. From one gram of callus used to initiate suspensions of 'GAF/Park' and '88Ab3073', 119.9 and 18.8 plants, respectively, were regenerated. The plants regenerated for various genotypes from agar-solidified or suspension culture experiments had normal growth and seed set. This study confirms high and sustained regenerative capabilities of 'GAF/Park', a restricted genotype due to the weedy Avena fatua genetic background and identifies alternative genotypes, especially 88Ab3073 for future tissue culture and transformation studies.