Abstract
1. The role of the age of wheat (Triticum vulgare) flowers in the crosses with rye (Secale cereale) pollen was studied in four wheat varieties in regard to the % of grain set, % of grain germination and the amount of the development of grains. 2. The function of ovules was kept as far as 9-13 days after the emasculation in different varieties. 3. In a tariety (Honkei No. 124) that showed low % of grain set, no difference of grain set was observed in connection with the age of flowers, while in all other three varieties, Norin No. 68, awnless Hiraki and Nisimura, a higher % of grain set was seen and a considerable diffeirence of grain set was found according to the age of flowers. 4. In Norin No. 68, awnless Hiraki and Nisimura, the germination of graihs was the highest when the flowers were pollinated 1 or 2 days after the emasculation. It became lower when the pollination was made for older flowers. 5. The weight df grain, which may show the amount of the development of grain, was the largest when the pollination was made ca. 2 days after the emasculation. 6. The percentage of the sudcess of wheat-rye crosses was highest when the wheat flowers were pollinated with rye pollen 1 or 2 days after the emasculation. 7. The most favourable age of wheat ovules in the crosses with rye pollen is 1 or 2 days after the emasculation.
