58 



THE BOTANICAL MAGAZINE. 



LVol. XXXVI. No. 426. 



F.j.I 



3-n 



F.6. TV 



f.g.T 



r 'S 



Hi 



F.g.-W 



Fiq. vn 



Fig. I a. The diagram of a chromosome having the factors V,D,H. 



Fig. I b. The diagram of the homologous chromosome having the factors 



v. d, h. 



Fig. II. Single cross-over occurring between D,V. 



Fig. III. One couple of chromosomes after the breaking took place in Fig. II. 



Fig. IV. Single cross-over occurring between V and H. 



Fig. V. One couple of chromosome after the breaking took place in Fig. IV. 



Fig. VI. Double crossing-over. 



Fig. VII. One couple of chromosomes after the double crossing-over. 



This statement is confirmed by the following experiments. After 

 the maturation in the germ cells of the F! plants, we can- verify the 

 presence of the eight kinds of chromosomes by back crosses (See 

 Table I). Although my experimental numbers were small compared 

 with others, I can see clearly the eight kinds of individuals each 

 having any one of the above mentioned eight kinds of chromosomes 

 through the back cross experiments that the homogeneous races 

 designate as the 5 having the factors v, d, h cross with the F A plants 

 which were obtained from the cross between the 5 and the homogeneous 

 races designate as the 9 A having the alleromorphic factors V, D, H, 

 and also having the reciprocal of the above crosses. 



Table I 



non-crossovers 



crossovers 



single 



double 



B.C. (5x9A)x5 

 B.C. 5 x(5x9A) 



Total 



DVH dvh Dvh dVH DVh dvH DvH dVh 

 42 36 4 2 24 33 6 5 

 4 4 11 3 13 



46 



40 



24 



total 

 152 



17 



169 



60 

 35.5 % 



15 



