8 BULLETIN 1014, U. S. DEPARTMENT OF AGRICULTURE. 
In 1920 eight varieties were grown. The dates of seeding were 
April 20, May 20, June 24, and July 20. The different seedings were 
made in single rows 66 feet long and 3.3 feet apart on uniform re- 
claimed river land that had been cropped to corn the previous year. 
The stands varied from one plant every 10 inches for the smaller 
varieties to one plant every 16 inches for the larger varieties. 
A summary of the data obtained from the experiments conducted 
in 1915, 1917, 1919, and 1920 is shown in Table 2. Data from the 
experiments conducted in 1916 and 1918 are not included in this 
summary, as only three seedings were made in 1916, and in 1918 two 
of the seedings were made in May. 
. RESULTS OBTAINED. 
In all the experiments there was a consistent decrease in the 
number of days from seeding to emergence as the date of seeding 
was delayed, although frequently the June and July seedings showed 
such slight differences that they were not recorded. The number of 
days from emergence to silking and from emergence to ripening 
consistently decreased except in the July seedings, which tended to 
show increases as compared with the June seedings. ‘The maximum — 
heights of most of the varieties were attained in the June seedings. 
The May seedings ranked second, the July seedings third, and the 
April seedings fourth in height of stalks. 
EFFECTS ON GERMINATION. 
When sown early the short-season northern varieties came up 
sooner than the varieties from the Central and Southern States. 
When sown later the differences in this respect usually were not 
apparent; where differences occurred the early-maturing northern 
varieties were found to be the first to come up. The results indicate 
that these northern-grown varieties are capable of starting growth 
at lower temperatures than the later maturing varieties of the Cen- 
tral and Southern States. Germination, as would be expected, was 
much more rapid from the later than from the earlier seedings. 
Seeds sown in April required an average of 17 days to come up to a 
stand, whereas those sown in July were as far advanced 6 days after 
eae 
EFFECTS ON HEIGHT AND RATE OF GROWTH. 
The average height of stalk and the average daily increase in height ° 
in the different seedings are shown in Table 3. | 
The total height and the daily increase in height were greatest from 
the June seeding. -The total height was greater from the May seed- 
ing than from the July seeding, but the rate of growth was slower. 
The least height and the slowest rate of increase resulted from the 
April seeding. 
