204 THE BEHAVIOUR OF POLYPLOIDS 



Thus autosyndesis occurs in the hybrids when it does not occur in 

 their parents. 



The simplest case of this is the formation of occasional 



I ( } V^ 9 I 







of I j(<<lr» 

 ( t. I ' till* 



■][J10IH»V.V. 



Fig. 72. — First metaphase in the tetraploid hybrid {^x = 28) of 

 Triticum Spelta {dx) X T. cBgilopoides {zx) showing tiie variation 

 in pairing from nucleus to nucleus. A, I'v + 5" + 141 ; B, 

 iiii _j_ 511 -j. 151 ; c. 2I" + 4" + 141 : D, I"! + 7" + III; 

 E, ID" + 8'. All chiasmata are terminal or subterminal. 

 X 1400 (from Kihara and Nishiyama, 1930. Cf. Fig. 58). 



quadrivalents by the hybrid between the tetraploid species Triticum 

 turgidum and T. durum which themselves have simple pairing as a 

 rule (D., 1 93 1 d). This indicates that among the pairs also in this 

 hybrid there may be some consisting of chromosomes derived from 

 the same parent. Thus segregation of the characters carried by 



