ANTHOCYANINS AND GENETICS 195 



1. That the amount of pigment in the pericarp of a variegated 

 grain bears a definite relationship to the amount of pigment in the 

 grains of the plant which grows from it. The relationship is such 

 that the more red pigment there is in the grains planted, the more 

 likely are the plants which come from them to produce self-coloured 

 red ears, and the less likely to produce variegated ears. 



2. That when F x red ears produced by selfing a homozygous 

 variegated-eared plant are selfed and sown they give rise to red-eared 

 and variegated- eared plants in Mendelian proportions; in the same 

 way when crossed with white-eared races, they behave as if they had been 

 produced by a cross between red-eared and variegated-eared races. 



3. That the Fj red ears arising from selfed heterozygous variegated- 

 eared plants behave in some cases as if they were hybrids between 

 red-eared and variegated- eared races, and in other cases as if they were 

 hybrids between red-eared and white-eared races. 



4. That the F a reds arising from crosses between both homozygous 

 and heterozygous variegated-eared plants and white-eared races behave 

 as if they were hybrids between red-eared and white-eared races. 



Thus, says Emerson, any interpretation of the above results must 

 take into account these facts: (1) that the more reel there is in the 

 pericarp, the more frequently do red ears occur in the progeny ; (2) that 

 such red ears behave just as if they were F x hybrids between red and 

 variegated, or red and white races. 



To explain these phenomena Emerson suggests the following hypo- 

 " thesis. The zygotic formula for a plant homozygous for variegated 

 pericarp may be regarded as VV ; heterozygous for variegated pericarp 

 as V . If in any somatic cell VV, from some unknown cause, a 

 V factor were transformed into a factor for self-colour, S, that cell 

 would then be represented as VS. Any pericarp cells descended from 

 such a cell would be red, and if all the pericarp cells of a grain were 

 thus descended the grain would be self-red, just as if the plant bearing 

 it were a hybrid between pure red and variegated races. Of the gametes, 

 moreover, arising from such somatic cells, one-half would carry V, and 

 one-half S, again just as if the plant were a hybrid between red and 

 variegated races. If both the V factors were changed to S, the grain 

 would be red as before, but all, instead of half, of the gametes would 

 carry S. If the modification from VV to VS should occur very early 

 in the life of the plant, or even in the embryo, then all the ears of the 

 plant might be self-red, and one-half of all the gametes, both male and 

 female, might carry S, and the other half V as in an ordinary hybrid. 



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