SEED COAT COLOR IN GARDEN BEANS. 



97 



in 1909 and in part from a cross made in 1911, which exhibited similar 

 behavior. In the 1911 cross there were four Fj plants, two of which gave 

 the progeny just referred to, and the other two gave the progeny shown 

 in cross 97a. Why these show such a different proportion we do not know, 

 for 97a must have been a successful cross, as proved by the appearance 

 of pole beans in normal proportions. It may be that the pollen grains 

 were not of the same constitution, or possibly stray pollen grains carry- 

 ing only black were involved in the F^ generation. The facts are here 

 presented in the hope that they may be suggestive to some other 

 investigator. 



Table XXI. — Crosses involving Creaseback. 



Crosses of other varieties with Creaseback are not shown in the table 

 because the results were complicated and somewhat uncertain. With 

 Golden Eyed Wax the Fi generation gave only black beans, and in F2, 

 10 black to 3 white. In F3 and F4 there appeared also coffee-brown (F) 

 and yellow (C) seeded plants in moderate numbers. One coffee-brown 

 plant bred true in the 9 progeny grown. 



When crossed with Warwick the results were complicated beyond hope 

 of comprehension. In the cross Creaseback X Warwick the Fi generation 

 is recorded as black with faint signs of mottling, while in the reciprocal, 

 which may have involved a different strain of the parent varieties, the 

 Fi beans were distinctly mottled, showing many distinct shades of pig- 

 ments. Apparently about all the pigments of both the red and yellow- 

 black series were involved. 



The behavior of the pigments in these reciprocal crosses does afford 

 some further evidence bearing on the hypothesis of a factor discussed on 

 page 75 and there called X. One strain of Warwick X Creaseback gives 

 the expected number of white beans, the ratio being 24 self-colored, 5 

 mottled and 9 white. Another strain yields no white beans but gives 30 

 self-colored and 7 mottled in both cases, approximately four times as 



