750 Fluctuations 



dom miglit be called seed-variation, as opposed 

 to partial or bud-fluctuation. And perhaps these 

 terms are more apt to convey a clear conception 

 of the distinction than any other. The germ 

 within the unripe seed is easily understood to 

 be far more sensitive to external conditions than 

 a bud. 



Multiplication of extremes by seed is thus al- 

 ways counteracted by individual variability, 

 which at once reopens all, or nearly all, the ini- 

 tial possibilities. Multiplication by buds is ex- 

 empt from this danger and thus leads to a high 

 degree of uniformity. And this uniformity is in 

 many cases exactly what the breeder endeavors 

 to obtain. 



We will treat of this reopening of previous 

 possibilities under the head of regression in the 

 next lecture. It is not at all absolute, at least 

 not in one generation. Part of the improve- 

 ment remains, and favors the next generation. 

 This part may be estimated approximately as 

 being about one-third or one-half of the im- 

 provement attained. Hence the conclusion that 

 vegetative multiplication gives rise to varieties 

 which are as a rule twice or thrice as good as 

 selected varieties of plants propagated by seeds. 

 Hence, likewise the inference that breeders gen- 

 erally prefer vegetative multiplication of im- 

 proved forms, and apply it in all possible cases. 



