194 MAKING BETTER PLANTS 



grafted upon an old tree of almost any sort, the new 

 variety of fruit may be secured and tested in the fourth 

 year from the time the experiment began, while if the 

 seedling is left to develop by itself, many more years will 

 be required. At the best, it is plain that one human life 

 is hardly long enough for complete experiments upon the 

 longest lived plants. Plant breeding is still an infant 

 science; and even more wonderful results are to be looked 

 for from it in the future than those so far secured. 



II. SOME RESULTS ALREADY SECURED 



140. Corn, a leading crop in the United States, has been 

 much improved both in yield and in quality. 



a. Increasing the yield. The average yield of corn in 

 the United States is still less than 30 bushels to the acre. 

 In Corn Club work, however, Walter Lee Dunson of Ala- 

 bama during the summer of 1913 grew 232.7 bushels of 

 corn on his acre of ground, at a cost of 19.9 cents a bushel. 

 Jerry Moore, another southern boy, is said to have raised 

 228.7 bushels of corn on his acre. These results were 

 secured partly by superior tillage, partly by selecting 

 superior seed. The latter factor is the only one of the 

 two which has a bearing upon plant breeding. 



In the average field of corn there are many stalks with 

 only poor ears or with no ear whatever. These barren 

 stalks usually produce an unusual abundance of pollen. 

 Their reproductive energy goes wholly to this. Since the 

 pollen grains from the barren stalks are more numerous 

 relatively than those from productive ones, the tendency 

 to barrenness may increase. A corn breeder counteracts 

 this tendency by removing the tassels of the barren stalks 

 before their pollen can reach the silk of the productive 

 stalks. This operation does more than counteract the 

 evil tendency: it positively strengthens the opposite good 



