No. 608] WEAK AWN IN AVENA CROSSES 



485 



Partially awned . 

 Fully awned 



Behavior of the Fully-awned Plants.— Seed of three 

 of the fully-awned plants was sown in pedigree culture 

 for an F3. The results obtained are shown in Table III. 



^WXED F, Plants— d14a: 



From this data, it would appear that the fully-awned 

 type is the pure recessive. We have already seen that 

 this type has very little influence on the Fi hybrid, and 

 that it appears in F2 in only about 25 per cent, of the 

 individuals. Here we find the fully-awned plants breed- 

 ing true. 



Behavior of the Partialhj-awned Fo Plants.— Twelve 

 plants which showed some awning in the second genera- 

 tion were planted in pedigree rows for F3. The per- 

 centage of awning in these plants varied from eleven to 

 eighty-seven. In spite of the wide difference as to per- 

 centage of awning, their behavior was strikingly similar. 

 With but one or two exceptions, the ratio of plants 

 not fully awned to those which were fully awned was 

 close to 3:1. A total of all these plants gave the 

 frequencies 419 : 118, or a ratio of 3.12 : .88. In this case 

 the deviation is 2.4 times as great as the probable error, 

 but this can be accounted for by the somewhat wide devia- 

 tions occurring in cultures 106 and 194. With the excep- 

 tion of these pedigrees, the deviations from the expectancy 

 are not more than twice the probable error. It is of 



