Effect of Gibberellin on the Vernalization of Winter Wheat and Barley

With an aim of knowing the effect of gibberellin on the vernalization of winter cereals, two kinds of experiment were conducted. The results obtained are summarized as follows:…… (1) Effect of gibberellin on the vernalization of immature embryos on the developing ear. Immature embryos of developing seeds of Hayaurehadaka, a winter barley variety, were vernalized. Spikes were detached 10 days after anthesis and chilled in a refrigerator at 5±3°C for 20 or 40 days with the stems immersed in water or gibberellin solution of different concentrations ranging from 1 ppm to 100 ppm. After treatment they were allowed to mature in room temperature. The seeds were stored at room temperature and then they were sown without cold treatment in the green house under long daylength (24 hrs.) It was observed that the longer the treatment, the more vernalizable they are. The gibberellin supply during the vernalization of immature embryos on the ear was effective in promoting flowering; the plants grown from the seeds treated by low tmperature and gibberellin concurrently were headed earlier and had a smaller number of leaves on main stem than the seeds treated with low temperature only. (2) Effect of gibberellin on the vernalization of germinating seeds. Cold treatment of germinating seeds has become the standard method of vernalizing cereals. The effect of gibberellin applied during the course of this standard method of vernalization, was also investigated. It was concluded that, in vernalizing varieties which possess high requirement for vernalization by chilling, the use of gibberellin was effective when the chilling was insufficent, but in the case of varieties possessing low requirement for vernalization by chilling, the effect were obscure.