16 



BULLETIN 33, U. S. DEPARTMENT OF AGRICULTURE. 



Table VI shows that the average yield in bushels per acre for all 

 varieties of spring wheat tested at Dickinson in 1907 was 23.8; in 

 1908. 21.5; in 1909, 32.3; in 1910, 19.1; in 1911, 8; and in 1913, 26.8. 

 The average yield of all varieties for the six years was 22 bushels per 

 acre. A comparison of the annual yields with the annual rainfall 

 shows that moisture is the principal factor in determining yield. 



SUMMARY OF WHEAT YIELDS. 



In summing up the yields for all years, the leading varieties of 

 each group of wheat were selected. Their actual and computed 

 annual and average yields are given in Table VIII. They are repre- 

 sentative varieties, improved by selection and the careful cleaning 

 and grading of the seed. There are two great groups of spring 

 wheat — the durum and the common. The varieties of spring com- 

 mon wheat grown in the Xorth-Central States may be divided into 

 three groups — fife, bearded fife, and bluestem. At Dickinson the 

 durum, fife, bearded fife, and bluestem varieties rank in jueld in the 

 order named. The average actual yield for six years (1907 to 1911 

 and 1913) of the two leading durum varieties (Kubanka and Ar- 

 nautka) is 11.5 per cent greater than the average yield of the two 

 leading fife varieties (Ghirka Spring and Rysting) and 29.4 per 

 cent greater than the average yield of the two leading bluestem vari- 

 eties (Crossbred and Haynes). There is little difference in the yield 

 of the fife and bearded fife varieties. 



Table YIII. — Actual and computed {annual and average) yields of seven stand- 

 ard varieties of spring wheat grown at the Dickinson substation from 1907 to 

 1913. inclusive. 



[The groups and varieties are arranged according to their actual and computed average yields.] 





Group and variety. 









Yield, per acre (bushels). 









1907 



190S 



1909 



1 



1913 



Average., 



C I. 



Xo. 



1910 



1911 



6 

 vears, 

 1907 to 

 1911 

 and 

 1913. 



5 

 vears, 

 1908 to 

 1911 

 and 

 1913. 



3 



vears, 

 1910, 

 1911. 

 and 

 1913. 



1140 



ACTUAL YIELDS. 



Durum: 



30.0 

 26.4 



22.6 

 17.6 



23.5 

 22.8 



23.5 

 22.3 



43.2 

 37 



28.9 

 33 



19.9 

 23.4 



2S.6 

 20.7 



23 



14.3 



6 13.1 



3.5 

 3 3.2 



9.5 

 7.7 



9.7 



6.9 



8.6 



31.2 

 30.9 



26.6 

 2S. 1 



25.6 



27.1 

 24.8 



26.2 

 24 



23.3 

 21.6 



24. 3 

 23.5 



23.4 

 22.4 



18.2 



1494 





19.2 



1 ."1 7 



Fife: 



21.6 



3022 





18.8 



3081 



Bearded fife: 



19.4 



3314 



Bluestem: 



Cross! redfX. Dak. Ne.318) . 

 Haynes (Minn. Xo. 169) 4 ... 



IS. 7 

 14 



22.3 

 21.4 



30.5 

 30 



20 



IS. 7 



20.2 

 19.6 



16.1 

 15. 5 



1 For 1907 and 1908, Kubanka (C. I. Xo. 1110); for 1909 to 1913, Kubanka Xo. 8 (C. I. Xo. 4063), a pure- 

 line selection from C. I. Xo. 1 HO male at Dickinson, X. Dak. 



2 For 1907 to 1910, Arnautka (C. I. Xo. 1491); for 1913, Amautka CP1 (C. I. Xo. 4046), a pure-line selection 

 from C. I. Xo. 1 191 mi le at Akron, Colo. 



a Estimate l from yiel 1 of Kubanka (C. I. Xo. 1 110). 



« For 19 17 to 1909, Haynes Bluestem (C. I. Xo. 3020); for 1911 and 1913, nayneT Bluestem (C I. Xo. 2870). 

 These two lots of seel were from the same original source, the Minnesota Agricultural Experiment Station. 

 ' Estimated from yield of Crossbred (C I. Xo. 3314). 



