2 BULLETIN 1248, U. S. DEPARTMENT OF AGRICULTURE. 
tion has been given to the proper spacing of sets of different sizes in 
order to provide for a maximum yield from each on a given area of 
land. 
The usual practice has been to space the sets in the row at such 
distance apart as was judged suitable for sets of average size. 
Under such conditions it is conceivable that large-sized sets' or whole 
tubers were spaced too close together to permit their maximum 
development, while the wide spacing of small-sized sets permitted 
a maximum yield per plant but undoubtedly a lower yield for a given 
area of land. 
It is self-evident that data obtained under such conditions may 
easily lead to erroneous conclusions regarding the relative value of 
sets of varying size. In fact, it is fair to assume that many of the 
discordant results that have been recorded from time to time are due 
to some of the causes mentioned. In comparing whole and cut seed, 
the element of moisture and an abundant supply of available plant 
food are important factors in determining yields. If either of these 
is lacking during the period in which the tubers are developing, the 
plants from whole seed as a rule will be most seriously affected. 
The whole tuber produces on an average a much larger number of 
stems and consequently a more numerous tuber progeny, many of 
which, unless well supplied with moisture and plant food, will not 
attain sufficient size to grade as table stock. The moisture supply 
during the period of germination may also have an important bearing 
on the relation of size and kind of seed to the stand. If there is a 
limited amount of moisture in the soil at the time of planting and 
immediately following, a small seed piece, especially if there is much 
cut surface permitting a considerable loss of water, may contain 
insufficient moisture and available food material to start the young 
plant and maintain its growth until it can derive its nourishment 
from the soil. Under favorable conditions for germination and 
growth the influence of the size of the set at this period of the plant's 
development is greatly minimized. 
The use of whole tubers for seed purposes offers greater possibilities 
in irrigated than in nonirrigated regions, because where irrigation is 
possible the question of moisture supply during these critical periods 
is eliminated. 
EARLY EXPERIMENTAL STUDIES. 
Among the earlier recorded experimental studies bearing upon the 
relative value of whole seed and cut seed of large-sized and small- 
sized sets that have come to the attention of the writers are those by 
Anderson, (7, 8) 2 Wimpey (103), Cochran (27), King (56, p. 92), 
Barrell (12), and Adams (2). 
In 1776 Anderson compared small potatoes planted whole with 
medium potatoes cut in two. Small potatoes averaging 0.275 ounce in 
weight and small potatoes cut in two averaging 0. 1 875 ounce in weight 
Were used. Large I -eve sets from the basal pari o\' Large tubers 
averaging 0.13 ounce in weight and large whole tubers averaging 6.5 
ounces from which all eyes but one had been removed were also used. 
The results of the season's study showed a slight increase in yield oi' 
the small whole potatoes over medium-sized tubers halved. Small 
ria] cumbers (italic) in parentheses refer i<> " Literature cited," at the end of this bulletin. 
