MENDELIAN LAWS OF INHERITANCE 297 



The possible combinations are seen in the following diagram. 



Male Gametes. 



Female RY RG WY WG 

 Gametes. 



RY 



RG 



WY 



WG 



a. Those marked (i) in which RY occurs will all be alike in 

 appearance, viz., round yellow peas, roundness and yellowness 

 being dominant characters. Of these there are nine. 



^. Three marked (2), viz., RG RG, WG RG, and RG WG, are 

 round green peas, R being dominant over W ; Y is absent. 



c. Three marked (3), viz., WY WY, WG WY, and WY WG, 

 are wrinkled yellow peas. R is absent, and Y is dominant 

 over G. 



d. One marked (4), WG WG, is a wrinkled green pea. 



The wrinkled green pea is a new variety, and it will breed 

 true when self-fertilised, having no Y or R in it. This is found 

 to be the case when tested. 



One of the three wrinkled yellow peas WY WY will breed 

 true. 



One of the three round green peas RG RG will breed true. 



One of the nine round yellow peas RY RY will breed true. 



The remainder are impure or hybrid in respect of one or 



