308 



GENETICS IN RELATION TO AGRICULTURE 



On one of the farms the same mutation has recurred several times. 

 Hayes believes that these mutations cannot be explained as the result 

 of accidental crosses. For in the large series of crosses that have been 



FIG. 150. The Stewart Cuban variety of tobacco, a very promising mutation. Plants 

 from seed sown under glass in December and transplanted to the open in May were twelve 

 to fourteen feet tall in September and had produced eighty leaves per plant. (From the 

 Journal of Heredity.) 



made in the Connecticut station in no case have new forms exhibiting 

 this tendency to indeterminate growth been obtained. 



Nilsson-Ehle discovered that in pure lines of oats occasional grains 

 appear that are aberrant either in color or in morphological characters. 

 The variations tested by him either bred true at once or after one or 

 two generations practically all of the progeny would breed true for the 



