14 Colorado Experiment Station 
leaf stalks growing from a stem of elongated character may be conceiv¬ 
ed to account for such tubers being circular rather than elliptical in 
cross section. The better the balance of tubers the flatter they are and 
the more run out the more nearly circular their cross sections. 
Strong side branches and the tendency of branches to turn upward 
appear to be coordinated with tubers being flattened, as are all our 
sorts to some degree when most productive, and with the fact that most 
of the eyes of such tubers are on the upper side. When first formed, 
such tubers are not flattened, the Rural for instance being, when newly 
formed, circular in cross section, and later flattened.* 
Aside from the above stated element of proper balance in potato 
plants, there is another element of balance, the tendency of stems 
either to stop growth before the tuber growth ceases, or to go ahead of 
the growth of tuber parts and tissue. The improved Peachblow potato 
is perhaps the best example of this. It has in many cases a recessed 
seed end, and in many cases it renews growth from this end, forming, 
especially with seedlings, which are more sexual, a series or even 
a “necklace” of tubers on one stem. In this variety also there is a 
noticeable tendency for growth to start from within the tuber, possibly 
from dormant buds. Large tubers of this variety crack very seriously 
and within the cracks are found what appear to be internal tubers or 
knots bearing eyes like those on the exterior surface of the original 
tuber. When flattened, large Peachblows seldom crack. 
The element of balance shows in Pearls in another way namely that 
tuber stems of more strongly sexual plants are more subject to the 
tendency of the branches to grow and form knots. Growers common¬ 
ly say that uneven watering occasions knots, and they are undoubtedly 
right, except that the tendency of previous years is perhaps a more im¬ 
portant factor. 
HARMONY OF PLANS FOR POTATO BETTERMENT. 
It is a great satisfaction to feel the entire harmony of objects 
sought in potato breeding. Within the bounds of a variety the largest 
yields, the most desirable flattened tubers, and the shallowest eyes, 
go together. Conditions that favor one of these qualities favor the 
others. The largest profits to growers, and best quality for the house¬ 
keeper come from the same fields. Undesirable cylindrical shape, 
undue length of tuber, bulging or “compound” eyes, knots, deep eyes, 
and irregular shape, altho affected by varietal differences, appear to 
have common causes and common remedies. 
Flattened seed tubers, other things being equal, may be expected to be 
most productive.. We have noted this with Snowflakes and have found the 
Russet to be. quick to respond to selection of wide seed tubers. At 
Carbondale, in 1910, we obtained from wide seed Russets 6,257 pounds per 
acre more than from slender round tubers of the same stock. 
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