214 



BREEDING CROP PLANTS 



TABLE LIII. RUST RESISTANCE IN TIMOTHY IN RELATION TO OTHER 

 CHARACTERS AS SHOWN BY VARIOUS DATA 



planting the seed so produced clones are tested for transmission 

 of the desired characters and also for uniformity. 



3. When sufficient seed is available, plots are sown broadcast 

 and tests for yield are obtained under ordinary field conditions. 



4. A selection which has shown performance ability is in- 

 creased in isolated plots and distributed to the farmers. 



CLOVERS 



The importance of clovers as forage crops and their role 

 in soil improvement make them of great economic value. Tri- 

 folium pratense, or ordinary red clover, is by far the most widely 

 grown. Alsike clover (T. hybridum), because it may be grown 

 in more acid soil than the other clovers, is favored in certain 

 localities. Some of the other clovers are white (T. repens), 

 crimson (T. incarnatum) , and the sweet clovers (Melilotus alba 

 and M. officinalis). All of these species are biennial or peren- 

 nial except T. incarnatum, which is an annual. 



Red Clover. It has been demonstrated several times that 

 the species T. pratense will set practically no seed when protected 

 from the visit of insects, particularly bumblebees. However, 

 this is not the only factor which influences fertilization. West- 

 gate et al (1915) found that moist soil and atmospheric condi- 



