No. 546] SHORTER ARTICLES AND DISCUSSION 365 



family of F 2 segregates gave the following ratio which may be 

 compared with the closest possible expectancy under each theory. 



Actual result 191 purple : 56 red : 180 white. 



Theory (a) 240 purple : 60 red \ 127 white. 



Th eory (6) 180 purple : 60 red : 187 white. 



This suggests theory B, but is not conclusive. Conclusive 

 evidence comes from the F 3 generation. On theory A, every 

 36 purple F 2 seeds should give on the average the following 

 results in F 3 : 



On theory B, every 27 purple F, seeds should giv 

 average these results in F 3 : 



8 ears segregating <i purple : 3 red : 4' 

 8 ears segregating 27 purple : 9 red : 28 i 

 The crucial test is the appearance of families she 

 12 purple : 3 red : 1 white. No such family has 

 On the other hand they did divide nicely into fami 

 of 9:3:4 and 27:9:28. Of the first type the 

 of nine families was 935 purple : 318 red : 436 whit 

 theoretical ratio on the basis of 9 : 3 : 4 would be 91 

 red : 422 white. Of the second type the total pi 

 families was 423 purple : 127 red : 396 white. T 

 sible ratio on the basis of 27 : 9 : 28 would be 400 p 



: 414 white. 



All other tests made corroborated the interprel 

 P factor can produce purple only when R and C i 



