1 28 PLANT-BREEDING 



young plants are checked in their development, the remain- 

 der will have more space, more sunlight, and more plant-food 

 than usual. Everybody knows that ears which have profit- 

 ed by such exceptional circumstances, are no true repre- 

 sentatives of their race and cannot be relied upon for seed 

 corn. Their excellence is not due to inheritance, they are 

 only personally superior without promise of an improved 

 progeny. Other ears may fall back from the average by 

 reason of unfavorable conditions, without having less value 

 as seed corn. It is a most interesting fact that often two ears, 

 especially when gathered from selected strains, apparently 

 may be exactly similar and notwithstanding this, give a very 

 different progeny 'when tested separately. It shows that 

 there is a kind of variability which has no direct relation to 

 inheritance, at least, not in the ordinary sense of the word. 

 It does not lead to racial improvement. Very little is 

 known, as yet, concerning the significance of the deviations 

 from the average type, which purely bred strains of corn may 

 produce by this unavoidable and inexterminable kind of var- 

 iability. We can state only that the characters of the single 

 ears of a pure race will differ somewhat from one another. 

 The characters are oscillating around the mean condition in 

 correspondence to the more or less favorable life-conditions 

 of the single plants. According to our experience with other 

 plants, the deviating ears of a pure race may possess the 

 power of transmitting the good yielding qualities of the strain 

 to the same degree as the average specimens. But, of course, 

 in practice, they can hardly be relied upon on account of the 

 always possible contaminations by foreign pollen. In all 

 cases where the uniformity of the ears and the kernels is show- 

 ing such fluctuating variability a choice of the best ears will 

 have to be made. But this choice is made in the interest of 

 a regular planting and a normal stand and not of a racial im- 

 provement by selection. It is difficult to appreciate the dif- 



