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, 19.4; 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 North-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 yield 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 
Jeading 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 VIII.—Actual and computed (annual and average) yields of seven stand- 
ard varieties of spring wheat grown at the Dickinson substation from 1997 to 
1913, inclusive. 
[The groups and varieties are arranged according to ther actual and computed averaze yields.] 
Yield per acre (bushels). 
A-veraze. 
} 
Chil: : 
2 y d variety. 
No. Group and variety | 6 : 3 
| 1907 | 1908 | 1909 | 1910 | 1911 | 1913 | years, | years, | years, 
1807 to | 1908 to} 1910, 
| 1911 1911 1911, 
and and and 
1913. 1913. 1913. 
ACTUAL YIELDS. | 
| 
Durum: 
1440 ERGQoY yay cll ar ye ella meh ee oe Shas! 0) || PA ay) BEX 19.9 aos le 26.2 24.3 18.2 
1494 PROTTV AIG KD) 2 setae: Oe ae oie 26.4 | 22.8 | 37 23.4 | 33.2 | 30.9 24 PS) 19.2 
Fife: 
1517 Ghirka Spring = ss eee 2 5-- 22.6 | 23.5 | 28.9 28.6 9.5 | 26.6 23.3 23. 4 21.6 
3022 RY SINO ee tena eeaeees 17565] 2220) | 30 20.7 Tod VW 28ek: 21.6 22.4 18.8 
Bearded fife: 
3081 Bearded Bifeves : ak ee eas et eer enc 23 EN dal WI ta on vel ee ek A | eae 19.4 
Bluestem: 
3314 Crossbred (N. Dak. No. 318) -| 18.7 | 22.3 | 30.5 | 14.3] 6.9 | 27.1 20 20.2 16.1 
3020 Haynes (Minn. No. 169) 4...) 14 21.4 | 30 513.1 8.6 | 24.8 18. 7 19.6 1925 
1 For 1907 and 1908, Kubanka (C. I. No. 14140); for 1909 to 1913, Kubanka No. 8 (C. I. No. 4063),.a pure- 
line selection from C. I. No. 1440 made at Dickinson, N. Dak. E } 
2 For 1907 to 1910, Arnautka (C. I. No. 1494); for 1913, Arnautka 6P1(C. I. No. 4046), a pure-line selection 
from C. I. No. 1494 made at Akron, Colo. 
8 Estimated from yield of Kubanka (C. I. No. 1440). 
4 For 1907 to 1909, Haynes Bluestem (C. I. No. 3020); for 1911 and 1913, Haynes Bluestem (C. I. No. 2870). 
These two lots of seed were from the same original source, the Minnesota Agricultural Experiment Station. 
5 Estimated from yield of Crossbred (C. I. No. 3314). 
