302 A CYTOLOGICAL INVESTIGATION OF SOME SPECIES 
CHAPTER IV 
RESULTS OF A PRELIMINARY INVESTIGATION OF THE CYTOLOGY OF SOME 
HYBRIDS BETWEEN SACCHARUM OFFICINARUM AND SACCHARUM 
SPONTANEUM 
$ 1. Some remarks about species-hybrids within the genus Saccharum 
especially about their fertility 
It has already been mentioned in the introduction that in the cros- 
sing of sugarcane at the Experiment-station of Pasoeroean different 
species have been used since many years. One has crossed varieties of 
Saccharum officinarum with Chunnee- and Kassoer-cane and as the 
hybrids, so obtained were, to a considerable part, fertile, it was pos- 
sible to cross these with one another or back with S. officinarum. The 
result has been the obtention of a large number of individuals of a very 
complicated hybrid nature, many of which are still fertile to a conside- 
rable degree. 
In 1916 JESWIET pronounced the opinion that Kassoer-cane might be 
a hybrid between the Black Cheribon-variety of S. officinarum and 
wild cane e. g. S. spontaneum. In the years 1918, 1919 and 1920 a great 
number of crosses have been executed by him between S. officinarum 
and S. spontaneum. The numerous individuals, obtained from these 
crosses are very simular to Kassoer, so that it is very probable that 
Kassoer has really arisen in this way. It can be said of these hybrid 
individuals, that plants, obtained from a cross of the same parents, 
show great similarity in habit, but are not identical, thus showing that 
the parents are heterozygous. In comparison with their parents they 
have an intermediate shape, but surpass them considerably in length; 
they luxuriate. 
It results from an investigation of a that of a total of 102 of 
these hybrid individuals 99 were fully fertile, while 3 were pollensterile. 
All of the former produced much pollen, an average of 75 % of which 
was well developed, thus pointing to a high pollen-fertility. Indivi- 
dually the percentage of good pollen oscillated between 40 and 100 %. 
But, even of the individuals with but 40 % of good pollen, the fertility 
may still be pronounced to be satisfactory as the quantity of pollen 
produced is very large. To give an idea of the fertility of these hybrids 


