Phenomena of Inheritance 



95 



RYT 



WGD 



RYT RYD RGT ROD WYT WYD WGT WGD 



?z 



Fig. 32. Trihybrid Diagram Showing Results of Crossing Peas Hav- 

 ing Round-yellow Seeds and Tall Stem (RYT) with Peas Having 

 Wrinkled-green Seeds and Dwarf Stem {WGD). Eight types of germ 

 cells are formed by the F, hybrid, as shown in the $ gametes above the 

 square and the 9 ones to the left of it, and the possible combinations 

 (genotypes) of these $ and 9 gametes are shown in the 64 small square 

 of which only 1 is pure dominant (upper left corner), I pure recessive 

 (lower right corner) and 8 homozygotes (in diagonal line between these 

 corners), The relative numbers of the different phenotypes are 27 RYT: 

 9 RYD:g RGT: 9 WYT: 3 RGD : 3 WYD : 3 WGT: 1 WGD. 



