Studies in Short Day Vernalization of Barley : 3. Difference in short day vernalization effect as affected by temperature

Abstract

The difference in the short day vernalization effect as affected by the temperature during or after the short day treatment was studied. The short day vernalization effect was not marked when low temperature was given during the short day treatment. There was a trend toward an increase in this effect with the rise in that temperature up to 18°C or 22°C. Variation in the heading date of the plants treated with short day under different temperatures was smaller than that of control plants. These were also true with respect to the difference in the short day vernalization effect as affected by the temperature after the treatment. The difference in the short day vernalization effect under different temperatures showed similar trends in any variety of different winter habits. The plants were treated with short day and were given various combinations of temperatures during the darkperiod and during the photoperiod. The short day vernalization effect under the low temperature during the darkperiod or the photoperiod was not marked. This effect increased with the rise in the temperature during the darkperiod up to 14°C or 18°C or with the rise in the temperature during the photoperiod up to 18°C or 22°C. The emergence of the final leaf was hastened by about one month when the plants were sown and treated with ten short days out of doors in October, while it was hastened by only 3 days when the plants were sown in the glasshouse and treated with ten short days out of doors in December.