On the Cross-over and Interference in 

 the Japanese Morning Glory. 



By 



Tokio Hagiwara. 



Outside of Drosophila, the only known case of the interference 

 of cross-over is that of primula sinensis reported by Altenburg. 1} 

 In the course of my genetic studies on the Japanese Morning Glory 

 (Pharbitis Nil), I have observed the phenomena of the double crossing- 

 over and interference, and the results of my experiments will be 

 given in the following lines. 



Linkage Group 



I have reported in the "Journal of the Scientific Agricultural 

 Society No. 273, 1921 " that three factors of the leaf, variegated (v), 

 rolled (d) and heart-shaped (h) make a linkage group. The variegated 

 (v) is- a simple Mendelian recessive to the normal. The rolled (d) is 

 a simple Mendelian recessive to the flat. I have reported the relation 

 between v and d in the " Botanical Magazine No. 399, vol. XXXIY 

 1920." I obtained the Fi plants having the genotype YvDd from 

 the cross YVDD X vvdd. The total sum of the separation numbers, of 

 Fa and F R is as follows : 



VD 



Yd 



vD 



vd 



Total 



498 



51 



48 



135 



733 



255 



27 



28 



74 



384 



F 2 experimental numbers 

 F 3 experimental numbers 



Total experim. numbers 753 78 77 209 1117 



Theoretical numbers 767.325 70.395 70.395 208.885 1117 



1) American Naturalist, Vol. LV, No. 636, 1921. 



