18 BULLETIN 1309, U. S. DEPARTMENT OF AGRICULTURE 
from all others. The rye seed used at the Arlington Experiment 
Farm has been obtained from the varietal plats, and no doubt con- 
siderable intercrossing has occurred. To reduce natural crossing 
between the varieties, the twentieth-acre plats of rye are interspersed 
among the plats of wheat varieties so that the distance between plats 
of rye varieties is 80 to 90 feet. To guard further against crossing, 
early and late rye varieties are alternated. The period during 
which a variety of rye blooms is so extended, however, that even 
between the earliest variety grown in the experiment (Abruzzes) 
and the latest (Rosen) there is opportunity for some crossing to 
occur. Flowering notes for three varieties in 1921 show that 
Abruzzes bloomed from April 16 to May 7. Von Riimker from April 
22 to May 8, and Rosen from April 26 to May 21. A similar over- 
lapping of the flowering period was recorded in 1922. The oppor- 
tunity for natural crossing between Rosen and Abruzzes is not so 
great as the dates of flowering indicate, because the extremely late 
dates in each case represent the flowering of the spikes on the smaller 
and later tillers. 
Rye usually has produced high yields. As in wheat, low yields 
occur when spring rainfall is heavy. Yield data have been obtained 
on 21 varieties and selections for part or all of the period from 1911,. to 
1923, inclusive. Annual and average yields of 19 of these are shown 
in Table 13, two selection- having been discontinued in 1913. The 
average yields of varieties grown during the 12-year period 1912-1923, 
show Abruzzes (C. I. Xo. 40) in the lead with 36.9 bushels to the 
acre. This variety grows rapidly in the fall and early spring and 
produces a fine quality of straw when lodging does not occur. 
Rimpau, a rye maturing a few days later than Abruzzes, ranks second 
in the 12-year period, with an average yield of 35.3 bushels. 
In 1915 the Von Riimker ryes, imported from Germany, were 
added to the experiments. One of these. Von Riimker Xo. 2 (C. I. 
Xo. 133). leads in yield for the 7-year period 1917-1923, inclusive, by 
3.4 bushels per acre, having an average yield of 41.2 bushels and out- 
yielding all 12 varieties in four of the seven years. It was classified 
in 1915 as a green-seeded rye. but at present approximately 30 per 
cent of the kernels are brown. 
St. John, a Swedish rye. ranks high in yield for the 7-year period, 
1917-1923. inclusive, with an average of 37.7 bushels. 0.1 bushel 
less than Abruzzes (G. I. Xo. 40). Both Von Riimker Xo. 2 and 
St. John are from five to seven davs later in maturing than Abruzzes 
(G. I. Xo. 40). 
Rosen rye, which has been grown during only five years, has 
produced good vields. Its average yield is 33 bushels, as compared 
with 34.7 bushels for Von Riimker X T o. 2 (C. I. Xo. 133) and 32.4 
bushels for Abruzzes (G. I. Xo. 40) in the same period. 
Leaf rust appears to be general on the rye varieties and especially 
on Rosen, the leaves of which are still green when the epidemic is 
at its height. Another plant disease not common at Arlington Ex- 
periment Farm was present in Rosen rye during 1922, when about 
50 heads of loose smut were observed. In 1920 a few smutted heads 
were found in Rimpau rve, but since then none had been noticed on 
anv variety until 1922, though an annual search has been made. 
