Callus Induction and Plant Regeneration from Barley Mature Embryos (Hordem Vulgare L.)

ABSTRACT

Immature and mature embryos of four Bulgarian winter and spring barley (Hordem vulgare L.) varieties were cultured in vitro to compare the levels of callus induction and plant regeneration. Immature embryos, 12–16 days after anthesis were aseptically excised and placed with the scutellum downwards on callus induction solid medium based on Murashige and Skoog (MS) mineral salts and supplemented with 2 mg/l 2,4-D dichlorophenoxyacetic acid (2,4-D). Mature embryos were aseptically excised from the imbibed seeds and were placed scutellum down on callus induction medium based on MS containing 2mg/l 2,4-D. The developed calluses were maintained on MS medium containing 1mg/l 2,4-D and 0.5 mg/l BAP 6-Benzylaminopurine. The regenerated plants were maintained on MS free hormones medium. Regenerated plants from both embryo cultures were vernalized and grown to maturity in soil. A strong variability was found among the genotypes in the in vitro culture response for both explants. For predominant number of the cultivars the germination ability was higher for immature embryos (Ruen, PV-101, Panagon) compared to mature. Immature and mature embryos from Ruen had excellent callus induction (72.2% and 97.8%, respectively) and the highest number of regenerated plants per embryo (9.3 and 13.3, respectively). A comparison of the responses of the two types of explants indicated that the mature embryos were more useful explants for plant regeneration, and therefore, being available throughout the year, can be used as an effective explant source in barley studies.