66 BULLETIN 1301, U. S. DEPARTMENT OF AGRICULTURE 
blue flowers, finer stems, and small brown seeds. The latter type is 
represented by North Dakota Resistant (N. D. R.) No. 114 (C. 1. 
No. 18), and Primost (C. I.-No. 12), which are both more or less 
resistant to flax wilt. The European seed type includes most. of 
the named varieties and the common unnamed flax of the seed-flax 
area. | 
Detailed data on yield, agronomic characters, and oil production 
of 14 varieties of flax grown on breaking at Mandan in 1914, 1915, 
and 1916 are presented in Department Bulletin No. 883. All varie- 
ties of the EHuropean seed-flax type yielded better than the short- 
fiber varieties. The leading variety, Reserve (C. I. No. 19), averaged 
17 bushels to the acre, with an average oil yield of 342 pounds to 
the acre. Select Riga (C. I. No. 2), with practically the same yield 
of seed, showed a higher oil content, averaging 354 pounds of oil to 
the acre. Damont (C. I. No. 3), Select Russian (C. I. No. 1), and 
Frontier (C. I. No. 17) produced practically the same yields of seed 
and oil as Reserve. North Dakota Resistant No. 114 averaged only 
12.2 bushels to the acre, with 233 pounds of oil. The yield of Pri- 
most was still lower. Varieties of the seed-flax type are best adapted 
to new lands. : 
In two years out of three a seeding rate of 20 pounds per acre 
roduced shghtly better results than either a higher or lower rate, 
ut the results of the experiment are not conclusive. On a well- 
prepared seed bed under semiarid conditions, there appears to-be no 
advantage in seeding at a heavier rate than 20 pounds. 
Ixperiments indicate an advantage in early seeding on clean new 
lands, although results of three seasons do not furnish sufficient data 
to warrant definite conclusions. The highest average yields were 
obtained from seedings between May 1 and May 18. Seedings on 
June 1, 1914, and on June 15, 1916, made decidedly lower yields 
than earlier seeding in each of these years. 
FLAX ON OLD GROUND 
The flax experiments at this station have been modified since 1916 
to meet the problems of weed control and flax diseases, especially 
flax wilt, which are becoming of increasing importance on the older- 
cultivated lands. Experiments in different methods of tillage have 
been conducted to determine the best methods of weed control. 
Extensive plant-breeding operations also have been carried on to 
develop high-yielding wilt-resistant varieties. 
During the years 1917-1922 in which the flax experiments were 
on old land, climatic conditions were exceptionally unfavorable. 
The previous treatment and preparation of the land for the plat experi- 
ments were not the same every year. In two seasons the flax 
varietal experiments were on fallow ground; two seasons they fol- 
lowed corn; one season they followed potatoes; and one season they 
followed sorgo. The land often was very weedy, as the dry seasons 
favored the growth of Russian thistles. In some cases the experi- 
ments were on land that previously had been cropped to flax. The 
land generally was double-disked and harrowed just before seeding 
in the spring. The previous cropping and treatment were essen- 
tially the same for all plats in each experiment in any one year. 
13 Accession number of the Office of Cereal Investigations. 
