BULLETIN 239. 



STUDIES ON BEAN BREEDING. I. STANDARD 

 TYPES OF YELLOW EYE BEANS.^ 



By Raymond Pearl and Frank M. Surface. 



Historical. 



Several years ago the Experiment Station began some breed- 

 ing work with bean&. The immediate problem for which the 

 work was undertaken was to procure true-breeding strains of 

 Yellow Eye beans. A great deal of difficulty has been experi- 

 enced by bean growers in securing strains which would come 

 even reasonably true to seed. In spite of careful seed selec- 

 tion for many years strains of these beans often continue 

 to throw small numbers of black, solid yellow, mottled or 

 white beans every year. Many of the large growers complain 

 that in order to secure a good price for their crop it is neces- 

 sary to hand-pick their beans every year. 



At the time our work was started it was believed that it 

 would be a relatively simple matter to secure pure-breeding 

 strains but our experience has shown that this is not the case. 

 It has been generally supposed that the bean flower is normally 

 self-fertilized ; that is, that the pistil or female portion of the 

 flower" is fertilized by pollen from the same blossom. It was 

 believed that this fertilization always takes place before the 

 blossom openS'. Three years ago we found that this is not 

 always the case, but that cross-pollination could be, and 

 under our conditions often was, brought about by bumble-bees 

 (B ambus sp.). 



If one watches a large bumble-bee working in a bean field 



^Papers from the Biological Laboratory, Maine Agricultural Experi- 

 ment Station, No. 84. 



