172 THE POTATO 



value and plants of lower value than either parent are 

 secured. A plant of high value is secured and grown 

 for a period of 3'ears in order to fix it. Those who 

 have regarded the valuable charadlers which led to the 

 selection of the individual as fixtures from the beginning 

 claim that this period of fixing is solely for the pur- 

 pose of elimination of the undesirable charadters, and 

 that it ought to be termed ' ' the elimination period ' ' 

 rather than ' ' the fixing period. ' ' The interrelationship 

 of different qiialities is not well known, but it has been 

 noted that a variety having a few thick stalks yields 

 large tubers, but few in number, while a number of 

 weak stalks is often found with a number of small 

 tubers. Early ripening and resistance to blight or rot 

 (^PhytophtJiora infcstans) are not generally found to- 

 gether. It is claimed that a large produ(5tion of seed- 

 balls goes hand in hand with a small produdlion of 

 tubers. T. A. Knight claimed that varieties which did 

 not bloom readily could be induced to do so by removal 

 of the soil from round the tuber-bearing stems, the ex- 

 planation offered being that the plant's failure in tuber 

 produdlion would stimulate the produ(5lion of seed.' 



In pollenizing varieties artificially the stamens should 

 be removed from the female parent with fine pin- 

 cers just as the bloom opens, or before, and the flower 

 enclosed in a paper or gauze bag. The proper time to 

 apply the pollen is known by the moist appearance of 

 the stigma. The pollen from the desired varietj- should 

 be dusted on the stigma on two or three successive 

 days. The bag may be removed when the stigma dies 



1 Philosophical Transactions, 1806. 



