22 BULLETIN 836, II. S. DEPARTMENT OF AGRICULTURE. 



C. I. Nos. 559, 564, 595, and 597 were obtained from different seed 

 companies and grown in 8-rod rows at the Woodward Field Station 

 for two or three years before being included in the varietal experi- 

 ment. 



The agronomic data for Dwarf broom corn are shown in Table 



VII, while the annual and average acre yields are shown in Table 



VIII, where comparisons with the Standard and Acme varieties are 

 made. 



The row space per plant in the different lots does not vary more 

 than about an inch in any one year, while the average row space for 

 all lots in the same year ranges from 6.3 inches in 1915 to 8.6 inches in 

 1916. From this standpoint the Dwarf varieties are directly com- 

 parable with the other varieties used in the experiment. 



The total growing period of the three lots grown during the entire 

 5-year period ranged from 84 days in 1918 to 114 days in 1917, with 

 an average of 94 clays for the period. This is the same average 

 period as for the Acme, but 9 days less than was required by the 

 Standard, which was 103 days in the same period. The average 

 proportion of suckers in these same three lots is 15.5 per cent, which 

 is 3.5 per cent greater than for Acme and about three times as high 

 as for the Standard, C. I. No. 556. 



In height C. I. No. 442 is consistently lower than any of the other 

 lots. Its height ranged from 2.3 feet in 1918 to 4.3 feet in 1915. 

 While the other two lots are of practically the same height in most 

 years, they show a difference of 6 inches in 1917, each reaching its 

 maximum of 5 and 5.5 feet, respectively, in that year. The new 

 lots added in 1917 compare favorably in height with the two just 

 mentioned. 



The average yield of good brush by the three lots grown during 

 the entire 5-year period ranged from 240 pounds in 1918 to 615 

 pounds in 1915. The average total yield produced in these same 

 two years was 278 and 752 pounds, respectively. The yield of good 

 brush was 85.8 per. cent and 82.2 per cent of the total yield. The 

 higher percentage of good brush was produced in 1918, when the 

 lowest total yield was made, and the lower percentage in 1915, when 

 the highest total yield was made. This tends to show that the per- 

 centage of good brush does not depend so much upon the quantity 

 of brush produced as on the conditions under which it is grown. 

 Growth that is too rapid or too slow during the fruiting period has a 

 bad effect on quality. The former makes coarse, burly, or twisted 

 brush and crooked heads, while the latter causes the brush to be 

 short and spiky. The greatest average length of good brush, 21.7 

 inches, was produced in 1915, and the shortest, 15.5 inches, in 1917. 

 In the former year the length of the poor brush was the same as the 

 good, but the crop made a rapid growth and developed some coarse, 



