34 BULLETIN 1155, U. S. DEPARTMENT OF AGRICULTURE. 
April 18, the average date of the first irrigation was April 26, and the 
average date of emergence was May 14. The earliest variety, 
Spagnuolo (C. I. No. 1585), was ripe 135 days after the first irriga- 
tion, the average date of maturity being September 8. The latest 
varieties required 180 days from the first irrigation to maturity. The 
average ripening date of the latest varieties was October 23. 
Standard, or late, Wataribune, which was grown so extensively in 
California from 1912 to 1917, is comparatively late. The average 
date of ripening for this variety was October 19, or 176 days from first 
irrigation to maturity. 
Colusa (C. I. No. 1600) is one of the most popular early varieties 
grown in California. The average date of ripening of Colusa rice was 
September 27 and the average number of days from first irrigation 
to maturity 154. Colusa is 22 days earlier than standard, or late, 
Wataribune,* and 7 days earlier than Butte. Onsen, a variety very 
much like Colusa, matures in about 151 days. 
Butte (C. I. No. 1564) was grown quite extensively in California in 
1918 and 1919. The average date of ripening for the Butte variety 
was October 4 and the average number of days from first irrigation 
to maturity 161. 
VARIETIES GROWN ON SMALL INCREASE PLATS. 
The yields of 28 varieties and strains of rice grown on small increase 
plats during the 7-year period from 1915 to 1921, inclusive, are shown 
in Table 25. One of the varieties listed in Table 25 is a medium- 
grain rice, Selection No. 133; two are long-grain rices, C. I. Nos. 461 
and 1168, and the remaining 25 are short-grain rices. 
The varieties and strains included in Table 25 with a few exceptions 
have not been grown long enough to determine their yielding capacity 
over a series of years. The results, however, show that the short- 
grain rices yield better than the medium-grain or long-grain rices in 
California. 
Our results at Biggs indicate that unless a variety does well when 
first introduced it will not become acclimated and better adapted by 
growing it for a series of years. Selection of varieties not well adapted 
to our conditions has failed so far to improve them for our section. 
The varieties that are adapted can be improved by selection unless 
they are pure-line varieties. 
