76 



MASS. EXPERIMENT STATION BULLETIN 185. 



and a formula of Yz for Blue Pod Butter, we should get a proportion of 

 6 mottled, 42 self-colored, and 16 white, which proportion is rather closely 

 approximated in both crosses 31 and 32. The crosses with Challenge 

 Black Wax seem to present different combinations of characters. Number 

 97 was one of the early crosses, and the obscure mottling earlier referred 

 to appeared, but no record was preserved. Cross 97c was made later 

 when the appearance of mottling was more clearly appreciated, and these 

 two may be of the same nature. Crosses 97o and 976 are probably alike, 

 and the failure of any white seeded beans to appear in 97a due to chance. 

 We are unable to explain the small proportion of white beans, unless it 

 may be on the basis of difference in the pigment complex earlier referred 

 to. 



In cross 247, Golden Eyed Wax X Creaseback, no mottled beans are 

 recorded in F2, but in later generations obscurely mottled beans do appear, 

 and it is not impossible that a closer study of the r2 generation would have 

 revealed their presence. Unfortunately these samples are among those 

 destroyed. 



This variety is worth further study and a full comprehension of its 

 behavior, and the reasons therefor would probably throw much light on 

 the inheritance of pigmentation, not only in beans but in a general way. 



Another variety that apparently behaves in a similar way is Crystal 

 Wax. Owen^ reports that crossed with Round Pod Kidney (Brittle Wax) 

 there appeared in Fj colored and dark mottled, nearly black beans, and 

 the F2 plants were 10 mottled, 24 self-colored and 10 white, nearly all of 

 the self-colored seeds being black. 



Mottling Patterns. 

 Among the commercial varieties of mottled beans two prevailing types 

 of mottling are evident. Both show as a ground color a sort of buff or 

 ecru. In the darker mottling, represented by Red Valentine and Refugee, 

 this color prevails over only a small part of the seed, while in the lighter, 

 represented by varieties of the Horticultural class, it covers three-fourths 

 or more of the surface. Some evidence indicating that this buff color is 

 the same thing in both light and dark mottled beans will be presented 

 later. When crossed, the darker type of mottling seems to behave as a 

 simple dominant in the single cross that has been made. 



Table VII. — Light and Dark Mottling. 



' Report N. J. Experiment Station, 1906, p. 456. 



