THE CYTOLOGY OF THE SUGARCANE ois 
Troeno (a form of S. spontaneum) has a very regular reduction-di- 
vision, and 56 chromosomes in the haploid phase, these additional 
chromosomes must doubtless have been derived from zoo POJ. 
The cytological investigation of G g2 showed furthermore that very 
frequently great abnormalities in microsporogenesis occur in this cane. 
Although some flowers showed almost normal divisions, this was not 
so in most cases. Rather frequently pollen-mothercells were found, 
which were much larger than the normal ones and contained 2or3 nuclei. 
When passing into metaphase these nuclei formed one large common 
spindle with very many chromosomes.The dyad-cells formed from such 
pollen-mothercells, were also much larger than the normal dyadsand 
contained larger nuclei. It was found also, that a normal homotype 
division did not occur as a rule in the case of G 92, tetrads were usu- 
ally not formed. 
The akon of the pollen, which always took place in connec- 
tion with the crosses to be made revealed a great sterility in the case 
of G g2. Of the anthers 80 % remained closed. Those which opened 
gave but little pollen, 50 % of which, moreover, contained starch. 
Crosses of S. officinarum x S. spontaneum are almost without excep- 
tion rather fertile and show a normal reduction-division. It is therefore 
not improbable that the irregular reduction division of G 92 and its 
poor fertility is due to its descendance from Loethers (via 100 POJ). 
2364 POJ. Fig. 20 pictures an anaphase of this cane in which 148 
chromosomes were counted, while the same number was found in an- 
other anaphase. An equal d od 
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diploid number I found 8° oo 
4 Pere © Dn 900 & 
in the case of some in- e a „= 100% 20.9230 o 
DI ED o® 
dividuals from the cross re „4e “ed pe 
Black Cheribon x Kassoer ® Be Fa > 8 of ow 
+ & 
(S. officinarum x spont- > 6 © 
aneum). In this cross also AA Rank 
the number of chromo- Fra. 20. 
somes of BlackCheribon Anaphaseof the heterotype division of 2364 POJ, 
RN doubléd™ so viewed from one of the poles. x 2300. 
that 80 Black Cheribon chromosomes have associated with 68 Kassoer- 
chromosomes, giving individuals with 148 chromosomes in the diploid 
phase. 2364 POJ has arisen from the cross of roo POJ (possessing in 
the diploid phase 9 chromosomes more than Black Cheribon) x Kassoer 
