92 



MASS. EXPERIMENT STATION BULLETIN 185. 



The Behavior of the Determiners of the Red Series. 

 According to the hypothesis already presented (see page 82), some 

 varieties carry a modifier which gives rise to a series of colors different 

 from the yellow-black series just considered. Only two members of this 

 series have been clearly recognized in this work, — one a dark or purplish 

 red designated by E, seen in Mohawk, and a lighter red seen in Red 

 Valentine which we have called D. Beans of the darker shade are changed 

 to the lighter on immersing in acid solutions, and a reversal of this is seen 

 on treatment with a solution of potassium hydrate. The darker alkaline 

 color seems to be dominant, and the limited data presented in Table 

 XVIII. indicate that crosses of these determiners behave as a simple 



Table XVIII. — Crosses of Light Red with Dark Red Varieties. 



monohybrid. As no light red beans appear in cross 215, both Golden 

 Carmine and Mohawk must carry the factor E. No signs of a buff- 

 colored bean have appeared in cross 258, therefore it is assumed that 

 both Red Valentine and Keeney Rustless carry the factor D, while the 

 latter variety carries the factor for the purplish red determiner E, which 

 is lacking in Red Valentine. 



The relations of Blue Pod Butter and the several varieties of the yellow- 

 black series have already been discussed. Table XIX. shows in a similar 

 way the relations of Blue Pod Butter and varieties of the red series. The 

 hypothesis of the "red" modifier M' as necessary for the expression of 

 these colors has already been advanced. Upon this hj'pothesis and that 

 of the two determiners E and D the facts shown in the table can be fairly 

 well explained, though a few cases are rather difficult of exj^lanation. 

 Blue Pod Butter carries the determiner E but lacks the modifier M'. 

 When this is supplied by crossing with Red Valentine, Low Champion or 

 Warwick, dark red E beans appear in dominant proportions. For some 

 reason the Fi beans in the Warwick crosses appear to have been lighter in 

 color, and were recorded as light red, or D. In later generations undoubted 

 dark red beans appear. Whether this is due to some environmental 

 influence or to an unknown genetic influence cannot be stated. This 

 has been recorded in two different years, and can hardly be an error of 

 observation. 



