EXPERIMENT STATION BULLETINS. 533 



freezing of potatoes in the field, (2) distance from market, the labor 

 cost necessary to dig and haul to market at the same time is too great. 

 The maximum economy is secured by marketing the crop more gradually, 

 resulting in both fall and spring shipment. This condition necessitates 

 winter storage and this is usually provided by a basement under the 

 house, separate root-house built into side hill, or pit storage. Pit 

 storage is usually only temporary for fall use in order to save handling 

 when the potatoes are to be sold before severe winter weather sets in. 



varietit:?. 



The principal varieties of potatoes grown are divided into two 

 classes, early and late varieties. 



The early varieties are the Irish Cobbler, Early Ohio and Bliss 

 Triumph. The late varieties are the Rural, Green Mountain and Russet 

 Burbank. In general it can be said that the green stem potatoes are 

 more subject to disease and insect injury than the blue and brown stem. 



The green stem varieties are the Green Mountain,, Burbank, Early 

 Ohio and Bliss Triumph; the blue or brown stem varieties are the 

 Rurals and the Irish Cobbler. Under similar conditions the Rural and 

 Irish Cobbler hills need to be planted 12 inches apart in rows when the 

 Green Mountain and Burbank need to be planted 15 inches to 18 inches 

 apart. 



The production of potatoes for use as table stock involves the pro- 

 duction of a quality potato product that meets the demand of the com- 

 mercial trade which wants a smooth shallow-eyed potato that is a good 

 shipper, a good keeper and at the same time is a good eating potato. 

 This combination is found in the Green Mountains and to a large degree 

 in the Rural type especially the Russet Rural. Both these potatoes 

 are adapted to the general market but when it comes to seed potato 

 production we find that the Green Mountain has not the resistance to 

 heat and drouth that the Rural has and so can not be raised for the 

 outside seed trade, except for certain areas that has similar climatic 

 condition to those found in the Upper Peninsula. The Rural type potato 

 is successfully grown under a wide variation of climatic conditions. It 

 stands the heat and drouth of the Corn Belt states better probably than 

 any other variety. Thus for a seed potato proposition the White Rural 

 or Russet Rural lends itself to the development of a large seed market. 



The early varieties mentioned are used principally at present for the 

 early home use before the late or main crop is developed. 



The commercial value of these varieties depends upon the production 

 of sufficient quantities so that carload lots can be shipped to the south 

 for seed purposes to those sections that furnish our spring and early 

 summer crops of early market potatoes. At present this market in the 

 central west is being supplied by growers located principally in Wiscon- 

 sin and Minnesota. 



SEED IMPROVEMENT. 



In order to promote the growing of better seed potatoes, work at 

 the Experiment Station has been undertaken, (1), to eliminate plant 

 disease, (2), to secure high yielding strains, (3), to maintain desirable 

 types, and (4), to select those strains that will improve the general 

 yield of potatoes. 



