CONSEQUENCES OF CHANGE 



once more. But it is not quite so fertile or so true-breeding as the 

 radish-cabbage tetraploid.Why is this? 

 At meiosis in the tetraploid P. kewensis the identical cliromosomc 



Pavia 

 2x=40 



hi 



ppo- 



castanum 



2x = 40 



\y 





carnea 



4x = 80 



POLYPLOIDY IN 



/tSCULUS 



Fig. 34. — The leaves, fruits and chromosomes of Aesculus carnea, a tetraploid of the 

 Primula kewensis type, and its diploid parents (after Upcott, 1936). 



from one parental species pair with one another rather than with 

 those of the other species. The frequency of chiasmata is almost as 

 high as in the diploid species (Table 15). But some cross-pairing 

 occurs and it can be seen in two ways. First, types that are no longer 

 intermediate appear in the progeny. They resemble one of the 



138 



