4/0 GENERAL MORPHOLOGY OF PLANTS 



quality. Experience and a growing insight into the laws of evo- 

 lution brought vastly improved methods, until now wonderful 

 results are obtained. The science of plant breeding is still much 

 of it in an experimental stage, but in some directions definite ends 

 can be planned and worked for with more or less certainty of 

 success, though in a majority of cases the length of time needed 

 to attain the desired result and the degree of success remains, 

 and will probably always remain, an unknow r n quantity. Studies 

 of experimental evolution will make the way more and more 

 clear in the future, just as the increased knowledge of the laws of 

 variation, adaptation, heredity, etc., gives plant breeders to-day 

 greater success than was ever attained before. 



655. Severity in selection. From the many thousands a 

 few, the most promising, are selected. This weeding-out process 

 of the undesirable forms, or " rogues " as they are termed, is 

 often called " rogueing." The thousands of plants which some 

 plant breeders discard, in order to select only the very few of the 

 highest quality, sometimes seems like ruthless destruction, but it 

 is this rigorous system of selection which brings the highest 

 success. One might paraphrase the old adage of " spare the rod 

 and spoil the child " by saying, " spare the rogue and spoil the 

 breed," The flowers from the offspring of these selected hybrids 

 are protected from cross pollination, and seeds are again planted 

 until the desired quality in fruit (color, flavor, size, period of 

 maturity, shipping quality, vigor, hardiness, etc.) is obtained. 

 In the case of plants which require several years of growth from 

 the seed before fruit and seed is obtained (as in the case of apples, 

 pears, peaches, plums, etc.), the time of the experiment can be 

 shortened by grafting the seedling shoot on a mature stock. If 

 the fruit is not satisfactory in all respects the process must be 

 continued. When the desired results are obtained it is then 

 necessary to fix the variety. When the variety can only be 

 propagated by seed this must be done by continued selection. 

 Some varieties will remain quite constant from the seed from the 

 first, and it is then only necessary to continue good cultivation and 

 selection of seed from the most productive plants which have the 



