Callus Induction and Plant Regeneration in Oats1

Abstract

Callus was initiated from immature embryos of 23 oat (Avena sativa L.) genotypes on Gamborg B5 or Murashige‐Skoog MS media containing 0.5 to 3 mg of 2,4‐dichlorophenoxyacetic acid (2,4‐D)/liter. These cultures were maintained by subculturing to B5 medium with 1 mg of 2,4‐D/liter every 4 to 6 weeks. Callus from the variety ‘Lodi’ has been maintained through 13 subcultures for 1 1/2 years and has retained the ability to regenerate plants. Callus capable of plant regeneration was also obtained from excised apical meristem tissues and germinating mature embryos on B5 medium containing 2,4‐D.Tiny green buds and leaves which developed from callus of 16 different genotypes formed shoots and plants when transferred to B5 medium without 2,4‐D. Ninety percent of the regenerated plants transplanted directly from culture medium to sterilized soil survived. One hundred thirty‐three plants representing 12 genotypes were grown to maturity. Most plants grew vigorously in the greenhouse and produced viable seed. Seed set ranged from complete sterility to 580 seeds from one regenerated plant. Although the growth of most of the regenerated plants appeared normal, some phenotypic and genotypic variability was observed. Cytological examination of meiotic cells from seven plants showed that two had the normal 21 bivalents at diakinesis while five exhibited aberrant meiotic configurations.The procedures used to regenerate large numbers of fertile plants from tissue cultures of many oat genotypes may ultimately prove useful in varietal improvement in oats and other species.