560 THE MONTHLY BULLETIN. 



SEED POTATOES.* 



By W. V. Shear, Assistant Horticulturist, United States Department of Agriculture, 



Stockton, Cal. 



During the past decade a gradually increasing emphasis has been 

 placed upon the importance of good farm seeds of all kinds. Improved 

 strains of wheat, oats, barley, corn, alfalfa, and other farm crops have 

 been produced. Not only is the particular strain considered of great 

 importance, but the vitality and powers of germination are also tested. 

 Where formerly much emphasis was placed upon cultural methods and 

 ways and means for the destruction of weeds and other crop pests, the 

 thought of the farmer is being directed more strongly toward the pro- 

 duction and use of better seed— and .justly so. In the chain of factors 

 which goes to produce a large crop of any kind the factor of good seed 

 can hardly be overestimated. Practically as much expense is put into 

 the plowing, harrowing, cultivating, irrigating, hoeing, and harvesting 

 of a 75 per cent or 50 per cent stand of any crop as for a full stand ; 

 often this low percentage of stand is due to poor seed, and the same 

 expenditure might have produced a 25 or 50 per cent greater crop, had 

 the proper kind of seed been used. 



In the case of the potato these considerations are all the stronger 

 because of the great expense connected with the care of the growing 

 crop and its harvesting. Good seed potatoes, then, comprise one very 

 important factor, without which success in potato growing can not be 

 secured. But how shall we define good seed potatoes and how can they 

 be distinguished from other potatoes? The final test of good seed 

 potatoes is the quantity of marketable tubers they will produce when 

 given the proper attention. That may, perhaps, seem self-evident ; but 

 it is the point of view which is sometimes lost sight of in examining 

 seed potatoes and some one characteristic of good seed potatoes obscures 

 this final test. Let us not forget, then, that good seed potatoes are pro- 

 ductive potatoes. What the grower wants to know, however, is the Avay 

 in which good seed potatoes can be distinguished from poor ones, either 

 when he goes to market to purchase his supply, or when he selects them 

 from his own crop. But do not jump to the conclusion immediately 

 that the writer is going to tell you in the next sentence just how this 

 may be done, because he believes it is impossible to determine absolutely, 

 from the examination of a potato, whether it will be productive when 

 planted. Usually, under our present market conditions, the only 

 criterion by which you can judge whether you have used good seed 

 potatoes is by the fact that, when the soil is thoroughly fitted and the 

 plants given good care throughout the season, at harvest time you find 

 you have a crop which equals the best that has been produced in your 

 locality. 



However, the writer does not wish you to infer that the examination 

 of seed potato stock has no value, or even little value. The examination 

 of seed potatoes is largely a matter of the elimination of the unfit rather 

 than a final determination of the fit. There are certain characteristics 

 Avhich determine the unfitness of potatoes for seed purposes which are 

 very important. Let us consider some of these. 



•Address before West Coast Potato Association, Palo Alto, Cal., July 27, 1915. 



