HEREDITY AND VARIATION 



221 



^ ■^'"^ 



White Disc 

 ww.DD 



Yellow Sphere 

 YYSS 



F,^ 



White Disc 

 WY, DS 



White Disc White Disc White Disc 



WW.DD WW,DS WW,DS 



White Disc 

 WY,DD 



White Disc 

 WYDD 



White Disc 

 WY, DS 



White Disc 

 WXDS 



White Disc 

 WXDS 



Whi+e Disc 

 WYDS 



White Sphere 

 WW5S 



White Sphere 

 WYSS 



Fig. 126. — Mendel's law of inheritanpe, where two pair.s of characters are 

 involved. In summer squashes, disc shape in fruit is dominant over sphere 

 shape and white color in fruit over yellow. A white disc crossed with a yellow 

 sphere gives an Fi generation all of which appear white disc. Wlien inbred, 

 this F\ plant produces an F< generation which is about ^/fe white disc, "^ le white 

 sphere, ?f e yellow disc and J-j e yellow sphere. Many F-; plants which look alike 

 have very different genotypes. The appearance of the fruit and the genotype 

 of the i)lant from which it came are given in each case. 



