44 BULLETIN 1155, U. S. DEPARTMENT OF AGRICULTURE. 
now the leading variety grown in California. It has, to a large 
extent, replaced standard, or late, Wataribune and Butte. 
Colusa (C. I. No. 1600) is an early short-grain rice, developed from 
a pure-line selection made in 1911 at the Rice Experiment Station, 
Crowley, La., by Charles E. Chambliss and J. Mitchell Jenkins from 
a Chinese variety obtained from Italy in 1909 through Dr. Haven 
Metcalf. This selection was grown in the nursery at the Biggs 
Rice Field Station in 1913, where it was later increased for distri- 
bution. In 1917 Colusa was increased commercially on about 200 1 
acres. This variety matures about three weeks earlier than standard, 
or late, Wataribune. It yields and mills well. The Colusa variety 
is best adapted to rich new land, but does not tiller or yield well on 
old rice land unless it is very rich. If left standing in the field until 
overripe it shatters quite badly, and on extremely rich land it is 
inclined to lodge. Large acreages of Colusa rice were sown in 1918, 
1919, and 1920. It has been and is one of the most popular early 
varieties grown on the new rice lands in California. This variety 
was first distributed as No. 1600, but was named Colusa in 1920, 7 
the name of one of the principal rice-producing counties in the State. 
Onsen is an early-maturing short-grain rice introduced by a Japan- 
ese at Biggs in 1918. Onsen is very much like Colusa, though it 
matures about three days earlier and lodges more on new land. In 
milling quality the two varieties are similar. Onsen is not as uniform 
as Colusa, due largely to mixtures. Quite a large acreage of Onsen 
rice was sown in California in 1920 and 1921. Onsen and Colusa are 
so nearly alike that there are no logical reasons why both varieties 
should be grown in California. Colusa is generally to be preferred, 
because it stands up better and is more uniform in ripening than 
Onsen. On certain soil types, however, Onsen apparentlv does better 
than Colusa (C. I. No. 1600). 
CALORO. 
Several selections from the first crop of Early Wataribune which 
was grown on the Moulton ranch, near Colusa, in 1913, were made by 
E. L. Adams while in charge of the Biggs Rice Field Station. These 
have been tested at the station and four of the best strains were sown 
in 1919 on a small commercial acreage. The four selections known 
as Selection Nos. 1561-1, 1561-2, 1561-3, and 1561-4 were sown on 
39.41 acres in 1919. The yields ranged from 6,711 to 7,874 pounds 
per acre. The average yield of the four selections was 7,345 pounds 
per acre. Selection No. 1561-1, now named Caloro, which appears 
to be the best, was increased again in 1920, and about 6,000 pounds 
were distributed in the spring of 1921. The name is made up of the 
first three letters of the State name, California, and the Latin word 
oro, meaning gold. This is the first pure-line variety of rice selected 
in California especially for California conditions which has proved of 
i Chambliss, Charles E. Rice growing in California. U. S. Dept. Agr., Farmers' Bui. 1141, 22 p., 10 fig. 
1920. 
