THE MONTHLY BULLETIN. 99 



as otherwise the land will be injured, and sometimes very serioiisly 

 injured, for the production of future crops of potatoes. 



However, there has been so much discussion of disease-free seed 

 potatoes, and the emphasis has been placed on potato diseases to such 

 an extent as to create the impression that freedom from disease is the 

 only important characteristic of good seed potatoes. While it is very 

 important that seed stock should be as free from disease as it is possible 

 to secure it, still the mere fact that a potato is free from any evidence 

 of disease does not necessarily establish the fact that it is a good potato 

 for seed purposes. The test of a good seed potato is "whether or not 

 when planted and given the proper care it will produce a large crop of 

 marketable potatoes. Productiveness is the final test of the seed stock, 

 whether it be potatoes or any other farm crop. That seed of any kind 

 should be comparatively free from disease would seem to be an almost 

 self-evident characteristic. Clean seed is only one of the qualities of 

 good seed or productive seed. Productiveness or non-productiveness is 

 as much a definite and decided characteristic of a potato as any other 

 quality. 



For a number of years past great interest has been taken by farmers 

 throughout the country in using productive seeds of all kinds. Pro- 

 ductive strains of wheat, barley, oats, corn and other crops are being 

 demanded and bred in many localities where these crops are grown, 

 and it is a well-recognized fact that not all seed of a given variety has 

 the same productiveness as other seeds of the same variety, even though 

 it may have all or most of the outward appearances of the more pro- 

 ductive strains. This fact applies with equal or greater force in the 

 case of potatoes. One potato or one lot of potatoes may seem, as far 

 as appearances go, to be as healthy and vigorous as another, and still 

 the former, when planted, may not yield nearly as much as the latter 

 because it has not the same productive capacity. 



If any grower will take the trouble to pick out from a miscellaneous 

 lot of potatoes twenty-five tubers which seem to be as perfect and uni- 

 form as can be found, and cut each tuber and plant the pieces by the 

 side of the pieces from the other tubers so that the yield from each can 

 be separated from the others, he will be likely to find during the season 

 a great difference in the behavior of the plants grown from the different 

 tubers, while most of the plants from the same tuber will very likely be 

 quite similar, some being uniformly large and productive and others 

 just as uniformly small and unproductive. If the yield from the unpro- 

 ductive tubers is planted the following year, and also the yield from 

 the productive ones, a much greater difference will be found in the pro- 

 ductiveness of the two lots. This difference will increase year after 

 year if the selection is carried through other seasons. In order to get a 

 high yielding strain of seed potatoes it is necessary to select year after 

 year for seed purposes the tubers from the best yielding hills. 



To produce seed potatoes of this character it is necessary to spend an 

 extra amount of time and money upon the seed plots ; but growers who 

 do this will find they will be amply repaid by the increased productive- 

 ness of their seed stock, and they should receive a correspondingly 

 higher price for such seed than the general run of market potatoes. It 

 has been demonstrated over and over again that such selected potatoes 

 have a much greater value for seed purposes than ordinary unselected 



