STUDIES tiN THE GENETICS OF FLOWER-COLOriW, ETC. 



117 



see some form of liukii{j;o, ami on tlie other the fi-ee assortment of the gametes. 

 Experimeuts for determiuing all sucli important points were ahxjady begun. 



Some fiu'ther breeding lias been pei-formed in respect to the present cross, 

 but I will here simply state shortly what I have found about the reds in 

 i^,. Of 20 reds in all which have appeared in F^, only two onld be selfod, 

 anil their oflspriuü; ( = F.) wore cxäiüinod ; the results wore as follows: — 



Hence we see that lioth reds examined are heterozygous in respect to It, 

 i. e. CCIii'lth. When H and Ji are linked in the ratio 5 : 1 : 1 ; 5 or 

 C : 1 : 1 : (J we should Imve CCHrbb : CCBItbh in the ratio 10 ; 1 yr 

 12 : 1 i-esiDeckively, and thus there is no wonder that we have met with no 

 homozygous reds at all, because only two reds were examined. 



Multiple Allelomorphism. 



One of my objects of investigation of the flower-colours of Poiiidaca was 

 t<j pui-sue, if we luive there a case of the so-called " multiple allelomoi-phisra " 

 of Morgan and Ids school : thus white, orange, flesh-colour, yellow, red and 

 magenta m om* varieties might be a series of multiple allelomorphs which 

 occupy the con'esponding loci in certain homologous chromosomes. We have 

 however above seen that the results of all crosses in Portidctca executed by 

 me ai'e very well explainable by means of usual unit feictoi-s. Tlie following 

 remarks might also be of some interest. If my exparimeuts in Poriidaca 

 had ended with the i^-generatiou, we might perhaps be led in certain 

 cases at least to conclude that we have then to deal with a case of multiple 

 allelomoi-phism. JFor instance, I have found that the i^.-oflfepnng ex redx 



t This magenta came to development, becaiise at least one gamete Villi was produce«! 

 by reversion. Similar facts were observed in respect to No. 24 (Table VIII), F^ -generation (dis- 

 cussion, p. 129) and No. 29 (same Table, discussion p. 127). 



