Whyte 



-35 — 



Research !n Vernalization 



Effect of Vernalizing Developing Ears of Petkus Winter Rye 1935: ■ 



When a larger number of ears was treated in 1936, the ears were placed 

 in a refrigerator while still attached to the stem, and in some cases whole 

 plants were treated in this way. The period of chilling was increased to 45 

 days, and final ripening was carried out at medium temperatures. The 

 ears were air-dried and the grain sown on May 31, 1937, without further 

 treatment with low temperature. 



10 20 30 40 50 



Age of embryo at harvesting (clays) 



T^EXT-FIG. 2. Spring rye. Relation between age of embryo at harvesting 

 and time to anthesis in resulting plants. 



Another figure from Gregory and Purvis' article referred to on opposite page. 



Vernalisation of Growing Embryos in the Developing Ear of Petkus Winter Rye 



1936: — 



