136 PLANT-BREEDING 



fest. Each farmer can gather the knowledge and expe- 

 rience, which this process requires, and a few days' work in 

 a season may secure great profits without any notable outlay. 

 Of course, the greatest profits will come to those who have 

 a taste for the work and are willing to give it the necessary 

 attention. The most successful farmer is the one who 

 adopts scientific as well as practical business methods, and 

 who is guided in his breeding work by a thorough knowledge 

 of the laws of variability. He must be prepared to discern 

 the direct effects of environments from the marks of heredi- 

 tary qualities. He has to appreciate slight differences, in 

 the hope of seeing their significance increased by the culture 

 of the next year. By breeding, the yield per acre can easily 

 be increased by five bushels, and it is evident that this in- 

 crease is pure profit to the grower. 



The field selection is, however, only preparatory work. 

 The real selection is obtained by the comparison of the pro- 

 geny of the chosen ears. All selection must be based on 

 performance, since the aim of the work is the improvement 

 of the hereditary qualities. Many an ear has been found of 

 excellent shape and size, with straight rows and perfect butt 

 and tip, with most uniform kernels of the most desirable 

 structure, but it has been rejected, because it lacked the 

 power of transmitting these qualities to its progeny. Often 

 of two ears chosen in the field, and exactly similar in all 

 respects, the one has given a generation which yielded double 

 the harvest of the other. The propensity to produce barren 

 stalks cannot be judged by the inspection of the ear, but it 

 becomes manifest in the generation cultivated from its 

 kernels. Many other instances could be given, and all of 

 them will point to the same conclusion, that the hereditary 

 qualities of an ear are a character which demands special 

 investigation. This investigation is the separate culture and 

 exact comparative trial of the generation grown from its 



