8 
Colorado Experiment Station 
eracy. Both No. 3 and No. 4 have been found only as single plants 
in the hill, which peculiarity may be attributed to strong tendency in 
the seed piece to grow single stalks and no side branches at the eye. 
No. 5 bears fertile pollen and large fruits with many vigorous seeds. 
It has more than one plant to the hill and loses the strong central char¬ 
acter, but all the branches are erect, while the tuber becomes a Pear 
shaped degenerate. There are of course forms intermediate between 
these types, but as a whole the steps are surprisingly distinct. 
Pearl intermediates and bastards are found in the crop from the 
same seed which under better conditions produces only Nos. 1 and 2. 
For instance, a lot of Pearl seed, grading No. 2, from Del Norte, pro¬ 
duced at Carbondale, in 1910, no intermediates or bastards, while the 
same lot of seed under the degenerating conditions of 1910 at Greeley 
produced many of both intermediates and bastards. We have found 
the same true with us time after time from seed sorted and restored, 
tuber by tuber by experts. 
Sexual Tendencies Stronger than Selection in the Greeley district. 
The writer for four seasons, commencing with *1905, practiced near 
Greeley hill selection* of seed potatoes. In 1908 he selected from hand 
dug hills in the field a carload of seed Pearls and in 1906 a half car¬ 
load. The tubers kept good in shape, even improved in outline, 
though the eyes were a little deep, and the reduced yields were ascribed 
to seasonal and other causes. The main stems became gradually 
stiffer. After the fall frosts the “first year’ vines were prostrate, 
their leaves in the ditches, and the stems showed white as they lay on 
the hill, while the “pedigreed’’ vines had stiff upright center stalks 
which carried a brown flag of frosted leaves. The fields could thus 
be told apart to the row by their color as far as they could be seen. In 
1909, on the same farm, because, it seems, the seed-bearing tendency had 
accumulated to override all other influences, the type and yield gave way 
to long cylindrical and irregular shapes with many bastards and seed 
balls. These Pearls in 1909 did very well at Pagosa and at Montrose 
and fairly well on the college plots, but, in 1910, from all these sources, 
on our various plots, and at Pagosa and Montrose, in private hands, 
showed their degeneracy of vine, tuber and yield. We have noted at 
Carbondale the gradual improvement of Pearls and other varieties long 
grown under ideal conditions, as compared with the type of Pearls 
more recently brought from places where they had approached the 
intermediate form. 
Blossoming of Pearls .—Neither the Blue Victor, the Pearl, nor 
the People’s when at its best blossoms at all. The buds form early on 
relatively obscure stalks, but do not swell, do not show any color be¬ 
sides green, and soon blast and break off. This is true of vine No. 1, 
and to a large extent of vine No. 2, which last is characteristic of the 
Greeley district. Vine No. 2 will sometimes show color in the buds 
before they fall, and adverse conditions may produce late buds of this 
sort on No. 1 ; while severe dry early conditions will incline the habit 
of No. 2 in August strongly toward that of No. 3, and late bloom will be 
*See this subject in Bulletin No. 175. 
