230 Plant-Breeding 



its parent ; but it may be said that those individuals that 

 grow in the most usual or normal environments are most 

 likely to perpetuate themselves. A very unusual condi- 

 tion, as of soil, moisture, or exposure, is not easily im- 

 itated when providing for the succeeding generation, and 

 a return to normal conditions of environment may be ex- 

 pected to be followed by a more or less complete return 

 to normal attributes on the part of the plant. If the same 

 variation, therefore, were to occur in plants growing under 

 widely different conditions, the operator who wishes to 

 preserve the new form should take particular care to 

 select his seeds from those individuals that seem to have 

 been least influenced by the immediate conditions in 

 which they have grown. 



Again, if the same variation appears both in uncrossed 

 and crossed plants, the best results should be expected 

 in selecting seeds from the former. We have already 

 seen, in the seventh chapter, how it is that crosses are 

 unstable, and how the unstability is likely to be the 

 greater the more violent the cross. " Cross-breeding 

 greatly increases the chance of wide variation," writes 

 Henri L. de Vilmorin, "but it makes the task of fixation 

 more difficult." 



It is very important, therefore, when selecting seeds 

 from plants which seem to give promise of a new variety, 

 to sow seeds of each plant separately, and then make the 

 subsequent selections from the most stable generation ; 

 and it is equally important that the operator should not 

 trust to a single plant as a starting-point, whenever he 

 has several promising plants from which to choose. 



7. The less marked the departure from the genus of 



