No. 610] LINKAGE IN LTCOPERSICUM 



617 



cross was made in such a way that one dominant factor 

 entered from each parent. The nmnbers obtained 



Found 49: 16: 13: 7 



Expected 48: 16: 16: 5 



do not indicate any linkage between these factors. 



Price and Drinkard's data indicate that there is no 

 linkage between shape of fruit and color of fruit in two 

 different crosses (agreeing with the data given in Table 

 V), none between foliage color and fruit color, and none 

 between foliage color and fruit shape. In these crosses 

 the numbers are too small to be sure of the conclusions 

 with regard to linkage. They give the results of a cross, 

 however, which shows complete linkage between green 

 foliage color and two-celled fruit, as opposed to yellow 

 foliage color and many-celled fruit. Only 24 plants 

 were grown, which were of two types only, duplicating 

 the parents. 



These characters, foliage color and loculation of ovary, 

 can not be the expression of the same factor because many 

 varieties are known with these characters combined in the 

 other ways. In fact the majority of the common garden 

 varieties have green foliage and many-celled fruit. 

 Neither does it seem probable that these dissimilar char- 

 acters form a series of multiple allelomorphs as some 

 cases of complete linkage, for instance, cob and pericarp 

 colors in maize, are considered to be. Although the num- 

 ber of plants is small, as the writers state, it would seem 

 that among 24 plants at least one new combination would 

 appear if the factors were independent of each other. 

 Larger numbers of a similar cross, studied by back 

 crosses in the more favorable way, will probably show 

 these factors to be partially linked. 



Crane (1915) reports a cross between varieties of toma- 

 toes differing in rather complex characters of inflores- 

 cence and fruit shape. He obtained figures which indicate 

 partial linkage in these characters, but states that "the 



