PRINCIPLES OF HEREDITY 15 



he studied were color of flower and shape of seed. He 

 crossed red-flowered ones with those haying white flowers, 

 and crossed those having wrinkled or angular seed with 

 those having round peas. 



Sixty blossoms were fertilized so that either the pollen 

 or the pistil came from a pea that had the round seed, 

 while the other gamete came from a plant that bore 

 wrinkled seeds. When these hybrid seeds grew, they all 

 produced round seeds. These round peas were planted, and 

 in the next generation there were 7,324 seeds, of which 

 5,474 were round and 1,850 were angular, or a ratio of 

 2.96 to 1. When the angular peas were planted, they pro- 

 duced only angular seeds, and continued so to do indefi- 

 nitely. One-third of the round ones produced only round, 

 and continued all round in later generations. The other 

 two-thirds of the round ones, or approximately half of 

 the whole number, produced both round and angular peas 

 in the proportion of 3 to 1. Of these, the angular ones 

 remained angular when planted, and one-third of the 

 round ones remained round, while two-thirds again broke 

 up into round and angular. 



Likewise he crossed peas with red flowers and white 

 flowers. When the seeds were planted, all the plants bore 

 red flowers. But in the next generation, of 929 plants 

 705 were red and 224 were white, a ratio of 3.15 to 1. 

 The white ones produced only white in the future. One- 

 third of the red ones produced only red, and two-thirds 

 produced both red and white in the proportion of 3 to 1. 



From these and other experiments he drew the follow- 

 ing conclusions: 



(1) It made no difference which way the cross was 



