112 SIRKS, THE COLOURFACTORS OF THE SEEDCOAT IN PHASEOLUS 
Monohybrid segregation. 


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Family | Brown. | Citroen. | Total. | Proportion in a total of 4. 
990% Att hybr. Fi 3 ae 3.0 :1.0 
1002 ” 99 ~ 30 7 A 3.24 : 0.76 
996 Spont. hybr. 10 3 13%! 3.08 : 0.92 
1003 = 53 5 5 10 | 272 
48. 16 2} TER SOG 
Dihybrid segregation. 
n ge ee | Proportion if a 
Family mes ‚Wagenaar Citroen | Total. Ly 35 al COME! 
987 Artif. hybr. 20 4 10 34 9,41 : 1.88 : 4.71 
1) A 5 9 2 3 14 10.28 : 2.29 : 3.43 
993 Spont. hybr. 20 10 8 38 8.42 : 4.21 : 3.37 
999 5 5 17 5 Ds ST 8.80 : 2.58 : 4.62 
1004, 5 14 4 319 "21" Sf 100785 05E 
Total 80 | .25 33 | 138 | 9.28 : 2.90 : 3.82 





The results are not at all in agreement with the expected propor- 
tion 12:3:1; in all families the numbers of the groups are in 
defiance of this theoretical supposition. They come nearer to the 
scheme 9:3:4 andinduce thus to another hypothesis, that will be 
given below in connection with the results from other crosses. 
4. Cross OF CITROEN X ROTJES. 
As indicated above, the race known as „Rotjes” is not always 
uniform; darker and lighter types of greyish brown can in most 
cases be discerned. The colour can also come nearer to a reddish 
brown; besides individuals with a brown navelring, sometimes, 
though. somewhat rarely, others without this racial character 
appear in cultures of this race. The cause of this mixture of 
types is for the greater part to be found in the difficulty of dis- 
cerning them; if spontaneous hybridization has occurred, its results 
will in most cases remain unobserved, and the hybrids will find 
occasion to propagation and segregation, while in other races with 



