26 
BULLETIN 124S, U. S. DEPARTMENT OF AGRICULTURE. 
EXPERIMENTS AT JEROME, IDAHO. 
Owing to unfavorable growing conditions during the seasons of 
1915 and 1918 the experimental data for these two years are not 
included in Table 11. The data for 1916 from the Charles Downing 
(Idaho Rural) studies show the largest net yield from 5-ounce halved 
tubers. The i-ounce whole sets were second, closely followed by 
4-ounce halved, 3-ounce halved, and 3-ouace quartered sets. The 
5-ounce whole tubers gave the highest total yield, 451.6 bushels. 
The 6-ounce whole tubers were second, with 425.4 bushels. The 
3-ounce whole tubers came third and the 5-ounce halved sets fourth. 
In 1917, owing to a scarcity of irrigation water, all crops were very 
much reduced, and in consequence the outstanding differences in 
net yield were smaller. For example, the highest net yield, which 
was from 4-ounce whole tubers, was 179.2 bushels. The next three 
amounts show 173.7, 172.8, and 172.7 bushels per acre, produced 
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Fig. 5.— Average yields in bushels per acre from Charles Downing potato sets of different weights at Jerome, 
Idaho, in 1916 and 1917. 
from respectively 6-ounce halved, 4-ounce halved, and 3-ounce 
quartered sets. These differences are too insignificant to have any 
value. The 4-ounce whole tubers also show the highest total yield. 
313.8 bushels. The 6-ounce, 5-ounce, and 3-ounce whole tubers 
follow in the order named, with 286.4, 284.4, and 275.2 bushels per 
acre, respectively. The 2-year average of primes for 1916 and 1917 
showed a net yield of 216.5 bushels from the 4-ounce halved tubers, 
214.3 bushels from the 5-ounce halved, 213.5 from the 3-ounce 
quartered, and 211.9 from the 3-ounce halved tubers. (See fig. 5 
for total yields.) 
In the case of the Russet Burba nk (Netted Gem) variety the data 
for 1910 (Table 11) show the highest net yield of primes from 4- 
ounce whole tubers. The 3-ounce halved sets come second, and the 
5-ounce quartered, 2-ounce halved, 3-ounce quartered . and 1-ounce 
whole tubers show very slight differences in yield. In total yield 
