Potato Culture in Colorado 
25 
growing of numerous varieties always has a demoralizing effect 
upon the market and upon prices. 
THE RUNNING OUT OF VARIETIES 
It is a common complaint among potato growers that a given 
variety, after being grown for a series of years in the same 
locality, or at least on the same piece of land, runs out, that is, 
shows a decrease in vigor and productiveness. Investigations 
tend to confirm the common opinion that varieties decline under 
the ordinary methods of culture and seed selection. It is un¬ 
doubtedly true that a good variety grown on a certain type of 
soil tends to show a decline, especially when no efforts are made 
to keep up the production through the selection of seed. The 
common practice of using the small potatoes or the screenings 
for seed must inevitably lead to a decline in yield, as poorer 
stock is being planted from year to year. Undoubtedly, the system 
of cultivation may have something to do with the decline, also 
the climatic conditions under which the grower is farming. On the 
other hand, we have abundant evidence that with proper seed selec¬ 
tion, proper cultural methods, the right kind of soil and climatic 
conditions, a given variety does not decline, neither in vigor nor 
productiveness, but on the other hand shows an actual increase. This 
would indicate that the decline in yield, as commonly believed, is 
due to preventable causes over which the grower has control. We 
know personally of several growers in the State who have been 
growing the same variety for the last twelve or fifteen years, 
and during this time there has not been any decrease in production, 
but on the contrary a considerable increase. These growers, how¬ 
ever, practice seed selection by the hill method, and grow the 
potatoes for seed separately in seed plots. With these facts before 
us, we are inclined to dissent from the general opinion that the 
varieties run out, but believe that the running out is due to the 
lack of seed selection and the lack of proper cultural methods 
and soil conditions. 
TRUENESS TO TYPE 
The standard varieties of potatoes grown in Colorado are 
recognized by a certain type or form that the tuber assumes when 
grown under normal conditions. While this statement is true, 
it should be born in mind that elevation, soil and climatic condi¬ 
tions influence the type to a marked degree, and that the grower 
can only hope to maintain a perfect type of the variety grown 
when he practices the best cultural methods and careful selection 
of seed that is true to type. 
In heavy soil, it is difficult to maintain the type of the variety, 
as in growing the tuber yields to the pressure exerted by the soil, 
