WHITE— STUDIES OF INHERITANCE IN PISUM. 



575 



(2.Q-2.6 cm.) pods. Between these two extremes are numerous 

 varieties with pods representing all gradations in size, each variety 

 having pods with a definite range of variation characteristic to it, 

 when the varieties compared are grown under similar environmental 

 conditions. The following list of varieties (by number) with their 

 green pod diameter range w'ill give a clearer idea of these differ- 

 ences : 



P43 0.8-0.9 cm. 



P35 i.i-i.i cm. 



P12 1.2-1.3 cm. 



P87 1.2-1.3 cm. 



P123 1.2 cm. 



P83 1-3-I-S cm. 



P72 1.4-1.6 cm. 



P76 I4-I-5 cm. 



P24 1 



P92 1 



P14 1 



P116 1 



P31 1 



P81 1 



P32 1 



P60 2 



P82 2 



S-1.5 cm. 

 5-1.6 cm. 

 5-1.6 cm. 

 5-1.7 cm. 

 5-1.7 cm. 

 5-1.6 cm. 

 6-1.8 cm. 

 0-2.5 cm. 

 0-2.6 cm. 



Results from Crossing. 



Tschermak (81) and Lock (54, 56) crossed narrow-podded 

 peas with wide-podded varieties and obtained in F^ either interme- 

 diates or dominance of the large pod type. 



In Fo, segregation was observed but the plants were extremely 

 difficult to classify as the pod width per plant distribution gave a 

 continuous series. For example. Lock crossed 13 mm. X 20 mm. 

 and obtained 18 F^ plants with pods of the following character: 



Mm. frequency classes 

 No. of plants 



12 13 14 15 16 17 18 19 20 

 36621 



In Fo, 32 plants were grown, giving the following frequency dis- 

 tribution : 



Mm. frequency classes 

 No. of plants 



12 

 I 



13 



2 



14 



5 



15 

 4 



16 



17 



5 



19 

 I 



21 



In F3, the narrow pod segregates did not breed true. Large 

 seeds were to some extent correlated with wide pods. 



In another cross (13 mm. X wide-pod Telephone), 14 F^ plants 

 had pods on the average as wide as those of Telephone. In Fg, yS 

 plants gave the following distribution. 



