
Ss 



- 
155 
season, selection can avail little. That the cause of rough 
potatoes is partially due to the soil is indicated by the fact 
that the tubers of a given variety are usually smoother 
when grown on sandy soil than on that which is hard or 
stony. ‘The knobs or prongs so often found on potatoes are 
believed by many to be due to a second growth taking 
place on the advent of rain, after a period of severe drought, 
and it is thought in such cases the starch largely passes 
from the parent tuber into the prongs, much injuring the 
| quality of the former. 
it is well known on the other hand that form is an in- 
herited character in the potato, because each variety has its 
own shape. 
April 29 three short rows were planted with single eye cut- 
tings made from the very roughest and most mal-formed 
tubers that could be selected, and three adjoining rows from 
the smoothest and most regular samples. The variety was 
the White Star. The crop was harvested Oct. 1 with the 
following result: 
The three rows grown from mal-formed tubers yielded 
665 tubers, of which 2038, or about 30 per cent., were more 
or less mal-formed. 
The three rows grown from the smooth potatoes yielded 
578 tubers, of which 164, or rather more than 28 per cent., 
were more or less mal-formed, showing that selection in this 
case exercised no material influence. 
WHEN DO THE TUBERS CEASE TO ENLARGE ? 
The question as to the stage of growth in the potato plant 
at which the tubers cease to grow larger, is one of some 
importance to the farmer, as it is sometimes desirable to 
dig a crop before the tops are entirely dead. In order to 
answer this question, if possible, on August 27 the soil was 
removed from several hills of potatoes sufficiently to expose 
one tuber in each, and of this the diameter was carefully 
noted, after which the soil was replaced. The hills exam- 
ined were of varying degrees of maturity. After the tops 
were entirely dead, the same tubers were measured again, 
with the following results : 
_ Of ten tubers averaging 1 8-4 inches in diameter, of which 
the tops showed the first stages of ripeness, as indicated by 
the blackening or yellowing of some of the leaves, four 
showed a slight increase in size. One had gained in diam- 
eter 1-4 of an inch, two 1-8, and one 1-16 of an inch. 
Of five tubers averaging 1 5-8 inches in diameter, of which 
the tops had unquestionably commenced to die, but were 
still quite green, only one showed any gain, and that but 
1-8 of an inch in diameter. 
