216 Alaskan Science Conference 



that the degree day requirements for growing grains in the 

 Tanana valley are much below the standards of the temperate 

 zones of Europe and America, barley being earliest and the best 

 adapted cereal crop here. All adapted sub-arctic grain varieties 

 mature in considerably shorter time than in the temperate zone. 

 This shortening of the growing period is evidently associated 

 with the second phenological phase extending from emergence 

 to first heading. Adapted chorotypes head in 40-50 days after 

 planting or 30-40 days after emergence, while in the Wisconsin 

 Experiment Station, for example, their chorotype grain varieties 

 head in 55 to 70 days after planting. Consequently Wisconsin 

 grown grains use more degree days and solar radiation units 

 for grain production than the Tanana valley grain chorotypes. 

 This is possibly explained by the longer hours of solar radiation 

 during the month of June in Alaska. Solar radiation may be 

 considered to stimulate early heading of grain crops in the 

 beginning of July. 



Another feature of the Tanana valley grown grains is the 

 high food value with the highest protein content on the Ameri- 

 can continent. By a series of chemical analyses made by several 

 private laboratories and by official tests by the U. S. Depart- 

 ment of Agriculture average content of protein in 1948-1950 

 in our grains was: wheat 17.1; barley 14.0; oats 15.3. 



Analyses of the same varieties of grain tested at Matanuska 

 Experiment Station were considerably lower: wheat 11.5; barley 

 10.4; and oats 10.4. High quality of grain, therefore, is a char- 

 acteristic of the Tanana valley regional types of grain, the 

 chorotypes, developed by the complex environmental factors 

 and particularly by the climatic elements of this regional en- 

 vironment. 



Long summer days with long hours of solar radiation also 

 have a definite effect on several biennial vegetable plants, like 

 spinach, Chinese cabbage and radishes, which tend to become 

 annual. This behavior of crop plants in the sub-arctic region 

 is just the opposite to the tropical zones where crop plants like 

 flax and cotton tend to become perennial. 



