Transfer of the ability to flower in winter wheat via callus tissue regenerated from immature inflorescences

Abstract

Using two wheat varieties (Triticum aestivum L., winter ‘Grana’ and spring ‘Jara’) the ability of callus from immature inflorescences to differentiate into new plants was studied. In the case of the winter wheat the requirement for vernalization of the newly developed plants to attain the ability for heading was investigated.

Callus was developed from 1–2 mm fragments of immature inflorescences, 5–10 mm in length, on Murashige and Skoog medium containing 1 mg l^-1 2,4-d, 3% sucrose and 0.6% agar, at 25° C and in continuous light of about 6.4 W m^-2 PAR energy. After 6 weeks of culture green centres of differentiation were observed. During the following 4 weeks culture on MS medium free of 2,4-d, leaf-like structures as well as a small number of roots were obtained. The regenerants were rooted on a half-strength MS medium, then transferred to pots of soil and placed in a glasshouse with 16 h photoperiod at a temperature day/night 23/17° C.

After about 6 weeks of culture in the glasshouse, almost all regenerants (98%) headed and were fertile, producing normal seeds, including the winter variety. The heading of winter plants under conditions excluding vernalization indicates that the callus tissue derived from a generative organ transmits the state of generative induction onto the developing new plants.