4 CIRCULAR 377, U. S. DEPARTMENT OF AGRICULTURE 



trolled was used in some cases, while in others a steam-radiator 

 heated room served this purpose. In no case, however, did the tem- 

 perature vary much except when intentionally induced. 



Seed treated at low temperature in the refrigeration room or at 

 high temperature in the electric oven were in constant darkness. 

 Seed treated at high temperature in the steam-radiator heated room 

 were subjected to a variation from total darkness to the intermittent 

 light of night and day. The duration of treatment with both high 

 and low temperatures was more or less arbitrarily determined, but 

 consideration was given to experience of others doing similar work 

 so far as data were available, and an attempt made to use optimum 

 time rather than to use time as a variable in the experiment. 



In the case of high-temperature treatments molds always gave 

 trouble and, while the use of disinfectants was attempted, no satis- 

 factory way was found for completely overcoming this difficulty. 

 Seedings in the greenhouse were made in large pots using an excess 

 of seed, and after the seedling plants were established the stands were 

 reduced to the same number of plants per pot for the different treat- 

 ments. Plantings in the open field and coldframes were made in 

 rows with the stands approximate. Plantings in the open field were 

 made at the Arlington Experimental Farm, Rosslyn, Va., and the 

 coldframe and greenhouse plantings were made in Washington, D. C. 



EXPERIMENTAL RESULTS 



In table 2 is given the results from vernalized seed of white lupine 

 (Lupinus albus), crimson clover (Trifolium incarnatum), hairy vetch 

 (Vicia villosa), Austrian Winter field pea (Pisum arvense), double cut 

 red clover (T. pratense), and white sweetclover (Melilotus alba). The 

 vernalized seed was in the cold chamber for 40 days (Mar. 16 to Apr. 

 25). One check lot of seed was kept in ordinary storage and sown 

 dry at the time of seeding the vernalized seed, while a second check 

 lot was kept moistened for 6 days (Apr. 17 to Apr. 23) and then dried 

 for 2 days (Apr. 23 to Apr. 25) before sowing on April 25, 1934, at 

 which time the vernalized and dry check seed was sown. 



In the case of the white lupine the check lots of seed, while making 

 as good growth as the vernalized seed, excepting the one lot in the 

 greenhouse, did not in any case come into bloom, while the vernalized 

 seed in all lots blossomecf and developed seed pods (fig. 1). 



Crimson clover check lots in all cases failed to blossom. This also 

 was the case with the vernalized lots planted in the open field and 

 coldframes, but the vernalized lot in the greenhouse bloomed and 

 made a larger growth than the check plants (fig. 2). 



The vernalized lots of hairy vetch seed bloomed earlier than the 

 dry seed check, while the swelled seed lot was in bloom at practically 

 the same time as the vernalized lot. 



In the case of Austrian Winter field peas the vernalized lots blos- 

 somed decidedly earlier than the check lots. 



The red clover lot of seed that was vernalized and grown in the 

 greenhouse blossomed earlier than the check lots; the lots in the cold- 

 frames all came into bloom on the same date, while all lots in the 

 open field failed to blossom. 



None of the vernalized or check lots of white sweetclover blossomed, 

 and the vegetative growth was about the same for all treatments. 



