1 2 
Developing, Good Strains of 
Part I. 
A NEGLECTED NEED.—Eugenics in the potato 
field have not received much serious thought 
in the past. Potatoes comprise a nation in the 
plant world that produces an edible crop in the soil 
out of sight of those who miss the evidence of things 
unseen. When harvest time comes, the entire prod¬ 
uct of all the hill families is thrown together, and. 
as usually occurs in this imperfect world, the work¬ 
ers help to maintain the living and the reputation 
of the drones. Too long has the impression pre¬ 
vailed that “spuds is spuds.” The purpose of this 
article is to show that this impression is a miseon- 
eeption. 
SELECTION FOR YIELD.—Tests b.v experiment 
stations and progressive growers have demonstrated 
the importance and practicability of improving yields 
by seed selection. These tests have shown up the 
nulls. This is really a point of advantage to the 
potato grower, since he is not compelled to “breed 
out" certain undesirable characteristics which are 
almost sure to result from a mingling of blood lines. 
The breeding of potato stock that is' true to type 
can thus be more quickly accomplished. Once the 
desirable type is established, the elimination of 
“sports” and those individuals showing a tendency 
to revert or to make undesirable changes is all that 
is necessary. 
RUNNING OUT.—It has been the history of most 
potato varieties to “run out” in about 30 years, 
while varieties of dairy cattle, for instance, improve 
with each generation, although some families may 
not. The running out of potato varieties, or their 
tendency to deteriorate in yield and quality, is 
brought about sometimes by successive cropping un- 
Seed Potatoes 
all these factors, there is now increasing realization 
of the importance of vigorous, disease-free seed. 
The writer has witnessed many instances in which 
the most careful attention has been given to the 
planting and growing of the crop, only to result in 
a disheartening failure owing to the use of poor 
seed, which the grower bought in good faith as the 
best obtainable. 
(JETTING VIGOROUS SEED.—A grower who 
desires to build up a high-producing strain of seed 
potatoes of any variety has at his disposal three 
methods which will result in greatly increasing 
vigor in two or three years. The first of these is 
the simplest, and consists in a careful inspection of 
the field at least twice during the growing season. 
The first inspection is made at blossoming time, 
when he can eliminate from his seed plots all plants 
'Deep and Thorough Cultivation Is Necessary. Fig. M8 
Digging Units In a Seed Test. Fig. \)50 
tuber families that do not produce, and that ma¬ 
terially lower the quantity and quality of the product. 
We learn, for example, that there are “Reds" in the 
potato world, which make a mighty bluff and attract 
attention by their enlarged tops or vines, but which 
fail to aid materially in the filling of the basket. 
Again, there are families that are weakened by in¬ 
sidious disease for past generations, and naturally 
cannot compete with their clean and vigorous neigh¬ 
bors. Many of these diseased groups make a fair 
art, and their later weakness is concealed by their 
strong relatives in the adjoining territory, so that 
they pass unnoticed. Further, some tubers may 
have had their vitality lowered by growing under 
trying climatic conditions, with the result of lessened 
ability to overcome some unfavorable fungus com¬ 
petition, which means nothing to those individuals 
der unfavorable climatic conditions, but it is prin¬ 
cipally due to the ignoring of all fundamentals of 
improvement by selection of the best individuals. 
Most of the seed potatoes used in the country are 
grown in Maine, New York, Michigan and a few 
other Northern States. Potatoes grown in the cool 
climate of these States are unquestionably more vig¬ 
orous for seed purposes than those grown as a main 
crop in districts farther south. This advantage has 
been materially lost, however, by the practice of 
using culls for seed and the failure to practice any 
methods of selection. 
IMPORTANCE OF GOOD SEED.—In many areas 
in the United States potatoes are grown as the money 
crop, and the farmers’ income is dependent upon 
the yield and price he secures for the crop. In such 
areas the grower understands thoroughly the im- 
sliowing lack of vigor, evidences of disease, and 
plants not true to the variety and type which he is 
seeking. A second inspection- should be made before 
the vines begin to die. At this time all plants show¬ 
ing evidences of disease or weakness should be re¬ 
moved. As a rule, the less desirable plants, from 
the standpoint of vigor, succumb earlier than the 
more desirable plants near them. Since the seed 
plot will probably be harvested at one time, it is 
necessary to remove the tubers from these undesir¬ 
able plants as well as the vines. This method, while 
it is very simple, will result in an improved strain, 
but the results will not be so quickly apparent as in 
the two other methods. 
HILL SELECTION.—The hill selection method 
consists in making individual hill selections from 
the growing plants by staking them during the grow- 
I'ntntn Field From Disease-free Seed 
On Eastern Shore of Virginia. 
Fig. f/J/9 
Variations in Vigor Shown in Vine Growth. Fig. J/5t 
"hieh retain their original vigor. In a word, th( 
it is vigor that counts most in getting a satisfacto 
yield of potatoes, other conditions being equal. 
LREEDING TO TYPE. —Breeders of Holstein a 
Guernsey cattle have an Advanced Registry, ai 
•fersey breeders have a Register of Merit where 
they list the high producers of purebred stoc 
breeders of other live stock have found it instruct! 
and profitable to organize for the purpose of eneoi 
aging high production. Why. then, should not gro 
ers of Green Mountain, Irish Cobbler and Rural i 
tntoes develop their stock along the same line 
l here is not so much difference in good breeding 
•tie animal and plant worlds as many suppose, 
the case of potatoes, there is. of course, the distir 
th'ti that new individuals are produced by a divish 
"t the parent instead of by the breeding of two ai 
porta nee of the right type of soil, the loams being 
preferred. The store of humus is maintained in 
an efficient way by the use of legume or non-legume 
cover crops, frequently supplemented with manure. 
Drainage also receives careful attention, and. when 
necessary, a complete system of tile drains is in¬ 
stalled. Heavy fertilization in the row with a chem¬ 
ical mixture containing three to five per cent am¬ 
monia, eight to eleven per cent available phosphoric 
acid and three to six per cent actual potash is prac¬ 
ticed in the trucking areas along the Atlantic, the 
quantity applied varying from 1,000 to 2,000 lbs. per 
acre. The importance of deep plowing and thor¬ 
ough culture is well recognized. Spraying for in¬ 
sects and fungus diseases with Bordeaux and an 
arsenical is practiced with a clear comprehension 
of its importance. With the careful attention given 
ing season. At harvesting time each hill so marked 
should be dug. separated and the desirable tubers 
saved for seed purposes. Many of these plants thus 
selected will not yield up to expectations the follow¬ 
ing year, but by again selecting them the undesir¬ 
able types may be eliminated the next season. 
THE PRACTICAL TUBER UNIT METHOD — 
The writer believes the most accurate method is 
the tuber unit system, which may be used to supple¬ 
ment the hill selection method. Tubers from the 
most desirable hills should be carefully selected and 
those weighing five ounces put aside for the tests. 
Before cutting these should be treated with corrosive 
sublimate to eliminate any external disease. The 
tubers are then cut longitudinally in four equal 
pieces. Any tubers showing internal discoloration 
bould be discarded. The four pieces, representing 
