i 9 22] STOUT— STERILITY 125 



the next generation of this family, the progeny of four strongly 

 self-compatible plants, 275 plants were grown. Of these only 44 

 were completely self-incompatible. There were, however, only 6 

 plants as highly self-compatible as the immediate seed parents. 

 The majority of the plants (182 in number) were feebly self- 

 compatible and did not produce any viable seeds to selling. This 

 family, however, was somewhat more highly self-compatible than 

 was the family derived from plant no. 1 of series 3, in the second 

 generation of which only 2 plants out of 53 produced viable seeds 

 to selfing. 



Selection for the highest grades of self-compatibility in B. 

 chinensis was also carried through the second generation. In the 

 F x generation, 26 out of 338 plants produced viable seeds to selfing. 

 In the F 2 , 5 out of 88 plants produced such seeds. The proportion 

 of self-compatible plants was low and remained about the same, 

 not being appreciably increased or decreased in the second genera- 

 tion. No plants classed as highly self-compatible were found in 

 the F 2 , but this may have been due to the proportionally smaller 

 number of plants grown in this generation. 



Four series comprising 86 plants were grown from seeds obtained 

 by crossing certain plants of the Fj. Of these, 25 were feebly self- 

 compatible and one plant produced viable seeds. The F t hybrids 

 between the two species exhibited the three types of sterility 

 characteristic of the parent species. There was no indication of 

 a general impotence of both sex organs (pistils and stamens) such 

 as often results from hybridity. During the time when flowers 

 opened normally, branches left to open pollination produced pods 

 and viable seeds, and about 100 plants of this generation grown 

 in the field and left to open cross-pollination produced pods in 

 abundance. 



As to mid-bloom self-compatibility, the F x hybrids were like 

 the pure bred parents. Relatively few were highly self-compatible. 

 In one series, derived from crossing a plant of a medium grade 

 self-compatibility and one completely self-incompatible, of 50 

 plants, 12 were fully self-incompatible, 14 were feebly self- 

 compatible, 19 were self-compatible of medium grade, and 5 were 



