FIELD CROPS 371 



expense. No farmer, however, is so poor but that he can have his 

 breeding patch of corn, wheat or potatoes. Indeed, if they but 

 knew it, they can ill afford not to have such a breeding patch to 

 furnish seed for their own planting. 



If one is to use the most comprehensive methods of breeding, 

 the operations become very complex and few farmers would have 

 the time to undertake the work on so extensive a scale. No matter, 

 however, what methods of breeding or seed selection the farmer 

 is pursuing he should be familiar with the general principles in- 

 volved. 



The fact that we are able to improve plants by selection de- 

 pends upon the occurrence of what are called variations. We are 

 accustomed to think of plants as very stable and uniform. As we 

 casually look over a field of Ox-eye daisies and admire their beauty, 

 we distinguish no apparent variability; all seem to be alike. Nev- 

 ertheless, if we examine the plants carefully and study the different 

 individuals we find that each one possesses certain peculiarities. 

 Some have large flower heads, others small flower heads ; some have 

 very many rays or petals, others comparatively few; some have 

 broad rays, others narrow rays. Some plants are tall, others short. 

 No two plants can be found which do not differ from each other 

 in some noticeable character. They present different facial ex- 

 pressions, the same as do people or cattle, so that we may recognize 

 different individuals apart after we have studied them and made 

 their acquaintance. We know the Ox-eye daisy family, vet we are 

 not accustomed to being introduced to Sam Ox-eye, Jim Ox-eye 

 and John Ox-eye and attempting to recognize their characteristics 

 so that we will know them when next they call. This, however, is 

 one of the interesting studies which the breeder pursues. Careful 

 gardeners learn to recognize the individual plants which they han- 

 dle day after day the same as the shepherd recognizes the different 

 members of his flock. These ordinarily slight variations which are 

 spoken of commonly as individual variations are what the scientists 

 now call continuous or fluctuating variations. 



All of the individuals of any species, race or variety, whether 

 wild or cultivated, show these individual variations. If we examine 

 the different seedling trees in nursery rows of maple or oak, or dif- 

 ferent corn or wheat plants in fields of the same race, we will find 

 them to present similar individual variations. In many cases such 

 variations are transmitted by a plant to its progeny in the same 

 manner that many of the individual characters or characteristics of 

 a human being are in part at least transmitted to his progeny. 



Such slight individual variations are the type of variation most 

 used by animal-breeders in selecting to improve the breed. In plant- 

 breeding such individual variations are also used when the breeder 

 is selecting to produce an improved strain of any race. If, for ex- 

 ample, the breeder desires to produce a heavy yielding strain of the 

 Pride-of-the-North corn, he would select individuals having the 

 maximum yield, plant these in an isolated place and continue the 

 selection year after year, until a high yielding strain of the variety 



