POTATO BREEDING AND SELECTION. 35 
ommended in Circular 113 of the Bureau of Plant Industry and 
Farmers' Bulletin 533, United States Department of Agriculture. 
Every progressive potato grower should have his selection plat, in 
which to grow his yearly selections; and, in addition, he should have 
his increase plat, where the promising selections may be increased for 
the field-crop planting. 
SUMMARY. 
The data presented seem to justify the following statements: 
(1) That the potato crop of the United States is of sufficient economic importance to 
demand a most careful study of all favorable and unfavorable factors influencing the 
yield. 
(2) That the economic use made of the potato in this country is relatively unim- 
portant when compared to that of Germany. 
(3) That deterioration of our cultivated varieties through improper cultural practices 
and through disease necessitates the improvement of existing varieties through the 
exercise of greater care in the selection of the seed and through the development of new 
seedling varieties possessing greater disease resistance or better commercial qualities. 
(4) That the term " plant breeding," when applied to the potato, should be con- 
strued as sexual rather than asexual reproduction. In other words, it is believed that 
a distinction should be made between "breeding" and "selection." 
(5) That the work of Goodrich as a potato-plant breeder was epoch making, in that 
it resulted in giving us the progenitor of the world-famous Early Rose. 
(6) That while the growing of seedling potatoes may offer greater possibilities than 
selection alone, the latter method can be practiced with much greater ease than the 
former. Breeding can be indulged in only by the few, while selection may be engaged 
in by the many. 
(7) That the almost total failure of our present-day commercial varieties to produce 
seed balls is due to male sterility rather than to imperfect pistils or ovaries. 
(8) That the commonly accepted theory regarding the inadvisability of allowing 
more than one or two seed balls to develop on a cyme, on the assumption that weak 
seedlings would result, is not substantiated in crosses 8708, 8709, and 8718, which 
developed five and six seed balls apiece. 
(9) That the data secured from some of the crosses indicate very strongly that some 
varieties are prolific seed bearers, while others are not. 
(10) That the tuber-unit and hill-selection methods of seed selection are chiefly 
valuable in pointing out the weak, unproductive, and diseased seed tubers. 
ADDITIONAL COPIES 
OF THIS PUBLICATION MAY BE PROCURED FROM 
THE SUPERINTENDENT OF DOCUMENTS 
GOVERNMENT PRINTING OFFICE 
WASHINGTON, D. C. 
AT 
15 CENTS PER COPY 
