No. 550] 



ALEURONE COLORS 



615 



them should breed true, four ninths produce a 3 : 1 ratio,, 

 and four ninths produce a 9 : 7 ratio. Similarly, if either 

 one of these two factors is homozygous, of the F 2 purples 

 one ninth should breed true, two ninths give purple and 

 red 3 : 1, two ninths purple and white 3 : 1, and four ninths 

 purple, red, and white 9:3:4. But if both factors are 

 heterozygous, out of the twenty-seven F 2 purples only one 

 should breed true; two yield purple and red 3:1; four, 

 purple and white 3:1; four, purple and white 9:7; eight, 

 purple, red and white 9:3:4; and eight, purple, red and' 

 white 27 : 9 : 28. 



The results of intercrossing Tom Thumb pop, Missouri 

 dent and California pop, so far as they are known at 

 present, might be obtained if the three varieties had 

 either of the following sets of formulae, or any of the- 

 modifications of them suggested below : 



Tom Thumb pop ICRP ICrP 

 Missouri dent IcRP or icrP 

 California pop icrp icRp 

 Among the allowable modifications of the above for- 

 mulae are these: The formulae for Tom Thumb pop and 

 California pop may be interchanged. Substitutions of 

 C for R and R for C may be made if carried throughout 

 the set. P may be present in any one or two varieties 

 and absent from any one or two. Where I is present in? 

 Missouri dent and also in one of the other varieties, R 

 may be present in all three varieties, absent in any one 

 variety, or absent in Missouri dent and either one of the* 

 other varieties. 



