28 CIRCULAR 4 21, U. S. DEPARTMENT OF AGRICULTURE 



when no variety tests were conducted. Grain variety tests were 

 continuous from 1923 to 1932. The number of varieties was in- 

 creased in 1926. From .1929 to 1932 the 10 varieties of wheat in- 

 cluded in the uniform variety test conducted by the Division of 

 Cereal Crops and Diseases were grown in cooperation with that Di- 

 vision. Wheat varieties in other years, and other crops in all years, 

 were grown under informal cooperation with divisions of the Bureau 

 of Plant Industry. 



The extreme importance of selection of varieties of grain to be 

 grown in this section is shown by the tables for wheat, oats, and 

 barley. Differences in yield between varieties of the same crop 

 grown under identical conditions frequently exceed differences ob- 

 tained under different crop sequences. For example, the difference 

 in yield between White Smyrna and Coast barley, a variety of the 

 type most widely grown, is greater than the difference between 

 barley grown on corn ground and that grown on summer fallow. 

 Poorly adapted varieties, like Hannchen, may yield only about half 

 as much as better adapted varieties. Xo variety of oats is so out- 

 standing as White Smyrna is among the barleys, but the loss in 

 yield that could be experienced through the selection of a midseason 

 variety like Swedish Select is clearly apparent. 



With both barley and oats, earliness is an important factor. No 

 late variety of either oats or barley produced yields comparable with 

 those of earlier varieties. The early varieties are comparatively 

 more productive in dry years than later varieties. Selection of the 

 variety to be grown plays an important part in distributing pro- 

 duction between years. 



The wheat varieties tested were more uniform in yield than other 

 grains, but even with wheat the selection of a good or a poorly 

 adapted variety may change the yield 20 percent or more. 



Variety tests of small grains were generally conducted on corn 

 ground under uniform conditions. Comparison of the best varieties 

 can be made to determine the relative productive capacity of the 

 different crops. Kubanka wheat, Brunker oats, and White Smyrna 

 barley were the most productive varieties during the period 

 1926-32. In pounds per acre the comparative yields of crops as 

 represented by these varieties were 852 pounds for wheat, 986 pounds 

 for oats, and 1,243 pounds for barley. These results are in harmony 

 with those obtained in rotation studies. 



WHEAT VAEIETIES 



Table 11 gives the annual and average yields of wheat varieties 

 from 1923 to 1932. With each variety, the yield for each year is the 

 average of three plots. 



