No. 610] LINKAGE IN LYCOPERSICUM 



613 



In these last two tabulations many of tlie crosses show 

 a deficiency of dwarfs, although the results as a whole 

 agree closely with expectations. However, the numbers 

 are too small to place much weight upon. 



In connection with another investigation I have ob- 

 tained considerable data on the inheritance of this char- 

 acter, by simply growing the seedlings in flats from 6 to 8 

 weeks, and then counting the dwarfs and standards with- 

 out setting the plants in the field, as in all the previous 

 cases cited. It is not always possible to distinguish all of 

 the two tj^pes of plants, with certainty, at this stage espe- 

 cially, if the plants are crowded and there are many small 

 stunted plants. However, counting the plants at this time 

 removes the possibility of unequal sampling when only a 

 part of the seedlings are set in the field, and also the pos- 

 sibility of differential viability in the field. The distribu- 

 tions in 5 Fo and 16 F3 ^copulations from heterozygous Fj 

 plants gave the following results : 



Dwarf Cliampion X Stone, 5 populations 1,103 437 



Dwarf Champion X Earliana, 1 population ... 186 67 



Dwarf Champion X Stone, 12 F,, populations . . . 1,707 730 



Dwarf Champion X Earliana, 4 F^ populations . . 571 149 



Expected 3,713 1,237 



Here the deviation from expectation is in the opposite 

 direction. There is an excess of dwarfs. It would seem 

 that too many of the small plants were classified as 

 dwarfs when they were really standards. Two of the 

 above Fo populations were grown longer than the others 

 in flats which were not so crowded, so that the errors in 

 classification, I believe, were more nearly overcome. The 

 following results were obtained : 



Dwarf Champion X Earliana, F, 186 67 



Total found 454 155 



