No. 566] INHERITANCE IN EARS OF MAIZE 



113 



taneously in the rudiments of every grain so that the 

 grains become self-red while the cob remains variegated. 

 We might, of course, account for the appearance of self- 

 colored grains on a variegated cob on the basis of sepa- 

 rate factors for cob and pericarp color 10 by the assump- 

 tion that one of these factors may be modified while the 

 other remains unchanged. But we should then have the 

 no less difficult problem of accounting for the universal 

 appearance of red cobs with ¥ 1 red ears without respect 

 to whether the parent grains stood on red or variegated 



Forced to its logical limit, our conception of the V fac- 

 tor is that of a sort of temporary inhibitor, an inhibitor 

 that sooner or later loses its power to inhibit color devel- 

 opment, a power that once lost is ordinarily never re- 

 gained. Of course it may be that there is present in varie- 

 gated maize merely a dominant factor for self-color, S, that 

 is temporarily inactive, but that sooner or later becomes 

 permanently active. Even if this be true, 8 as an active 

 factor and S as an inactive factor are certainly as distinct 

 in inheritance as they are in development and therefore 

 deserve to be designated separately. And since in one 

 case there results self-color and in the other variegation, 

 the factors may as well be called S and V as anything else. 

 It is of course also conceivable that the S factor may re- 

 peatedly arise de novo, though this seems very unlikely. 



Whatever our conception of the nature of the factors 

 for variegation and for self-color in maize ears, these 

 factors are certainly as distinct in inheritance as any two 

 factors could well be. Moreover, there is abundant evi- 

 dence, which can not be given here, that they are strictly 

 allelomorphic, as indeed they must necessarily be if one 

 arises by modification of the other— this on the assump- 

 tion that the factors are definitely localized in certain 



Ann. Rp t . Nebr. P Agr. Expt^Sta., 24: 59-90. 1911. 



11 This problem is discussed in another paper on the simultaneous modifi- 

 cation of distinct Mendelian factors. Ameb. Nat., 47: 633-636. 1913. 



