Planting 155 



the seed will, at some size, be cut too small to insure a 

 good start to the plants. 



(6) As noted above, salable tubers used as seed usually 

 out^'ield cull seed, because of the fact that a larger portion 

 of the culls come from weak, diseased or degenerate hills. 

 The cull is not poor seed because small, but because there 

 is a greater chance that its inherited vigor is low. In 

 cool and wet climates, like those of Scotland, Ireland, 

 and Maine, there is less risk of small seed being injured 

 in vigor than in climates too hot and dry for the best 

 growth of the potato. The use of the systems of field 

 seed selection to find the strain having the greatest 

 inherited vigor with seed plots to multiply the selected 

 seed produced a stock of which the small culls may be 

 sa\'ed for use as seed. 



Experiment stations have found conflicting results in 

 stud}'ing the relative value of eye in different parts of the 

 tuber, which need further investigation. The eyes at the 

 seed end of the tuber start first to grow and are practically 

 the only ones which grow under greening in the sunlight. 

 When these seed-end eyes start sprouts, which are broken 

 off in handling before the others start the vigor is likely 

 to be more equal. Observations indicate that the eyes 

 nearest the stem end, particularly with varieties having 

 few eyes as the Rural type, are the ones most likely to 

 fail to grow and are the ones from which degenerate 

 strains originate. Under the present state of knowledge 

 of the subject, it is safest for growers to cut seed in such 

 ways as to have the seed end eye on as many of the cut 

 pieces as possible, and to allow a slightly larger amount 

 of flesh to the pieces with stem end eye, to make up for 

 their slower starting growth in spring. 



Smaller seed pieces can be used with fertile soil than 



