Plant Breeding 



275 



then produce a flower cluster. The new varieties found by the 



plant breeder occurred as a few scattered plants, among the 



hundreds of acres grown in the state. 



These plants had indeterminate growth ; 



that is, the stem continued to produce 



leaves until the end of the growing season. 



Seeds were secured by transferring the 



plant to the greenhouse. The average 



number of leaves on these plants is 



seventy, and the yield of tobacco per acre 



has been increased 90 per cent. Since 



the cost of growing a crop is nearly the 



same in both cases, the increased yield is 



largely added profit. (See also page 205.) 



By the selection and propagation of 

 timothy plants of large size for a few 

 years, the Cornell Experiment Station was 

 able to furnish seed to growers of hay 

 which increased the yield 36 per cent 

 over ordinary timothy. 



At the Maine Experiment Station ex- 

 periments in the breeding of oats led to 

 the separation of varieties w^hich gave a 

 yield of 80 bushels per acre, where the best commercial varieties 

 produced but 75 bushels. 



Better varieties for particular climates. The Florida Velvet 

 Bean was formerly confined to Florida and the Gulf Coast. By 

 the selection of early varieties which suddenly appeared at several 

 different places, the plant can now be grown throughout the cotton 

 belt, and there are in our Southern states more than six million 

 acres devoted to this crop. 



Plums suited to the Northern Plains region have been produced 

 by crossing the Japanese and European plums with the wild plum 

 of the region, and selecting the best of the resulting hybrids. 



Fig. 173. Variations in 

 length of timothy spike. 



