SEED SELECTION AND GROWING 47 



harvested promptly when mature. Too often this 

 characteristic is not found in either garden or field 

 beans and this is suggestive of one line of breeding. 

 Another very important 'feature in the case of field 

 beans is breeding for productiveness. The pods must 

 be abundant and well filled. The chemical com- 

 position of the bean seed will doubtless stand im- 

 provement and since beans are highly nitrogenous 

 It would seem amiss to attempt to increase the 

 starch contents at the expense of proteids. In 

 snap beans the pod is a very important feature yet 

 it cuts a very small figure in the case of field beans. 

 However, for field beans the pod should be green, 

 not yellow, tough and stringy rather than tender 

 and stringless. An added reason for tough pods 

 in field beans is the comparative ease with which 

 they are thrashed. The cross fibers in the pod 

 walls are the special agents for opening pods and 

 scattering the seed. They have been bred out of 

 some cultivated beans for obvious reasons, with 

 the result, however, that these types are very diffi- 

 cult to thrash. A tender pod, particularly if it has 

 been wet often after ripening breaks into pieces and 

 adheres to the seed in thrashing, while tough pods 

 still letain much of their original tendency to split along 

 the sutures. Tender pods would be a great dis- 

 advantage in field beans. 



Points of selection. — The first thing to do if one 

 would improve any plant is to study the existing forms 

 of that plant. Intelligent. work in plant breeding must 

 follow a systematic study of the varieties already 

 available. It is not enough to know the general 

 racial character of beans. Individuals of the same 

 race vary greatly in vigor and productiveness, if 



