A STUDY OF FACTORS INFLUENCING THE YIELD OF POTATOES 1215 



TABLE 53. PER CENT OF GROWERS DUSTING SEED WHO USED EACH MATERIAL 



dusting was not ascertained from all the growers who followed this practice. 

 In the cases in which it was not ascertained, it was listed as Unnamed. 

 Land plaster was shown to be the material most commonly used, with 

 sulfur second. About two- thirds of the growers in Franklin and Clinton 

 Counties who dusted, used air-slaked lime, which was not used in any 

 other region. Evidently, because of the likelihood that they cause scab, 

 neither form of lime has been popular, nor have wood ashes. 



TYPE OF SEED 



Probably no other phases of potato culture have received more experi- 

 mental attention than those bearing on the relation of type and amount 

 of seed planted, to yield. In attempting to correlate type of seed with 

 yield, however, the all-important factor of amount of seed used has too 

 often been neglected, both in the method of experimentation and in the 

 conclusions. This has led to confusion, false conclusions, and a con- 

 glomeration of published data of questionable value. To be of real value, 

 such tests must take into account both the types of seed used and the 

 amount of each planted. The relation of type of seed to yield may be 

 treated under the following headings: (1) large as compared with small 

 tubers for seed, (2) whole as compared with cut seed, (3) large as compared 

 with small seed pieces, and (4) number of eyes. In reviewing the litera : 

 ture on each of these points, it has been difficult to reach conclusions, 

 because of the confusion, inmost cases, of one factor with one or more of 

 the others; and very often the amount of seed planted has been entirely 

 neglected. 



Large as compared with small tubers for seed 



More than thirty years ago, Adams (1889) compared the yields from 

 large, medium, and small whole seed, and found an increase both in total 

 and in marketable yield with each increase in size of tubers used. * With an 



