A METHOD OF IDENTIFICATION AND DESCRIPTION OF 



SUGAR CANE VARIETIES, AND ITS APPLICATION 



TO TYPES GROWN IN PORTO RICO. 



By n. D. OowGiLL, Plant Breeder, Insular Experiment Station. 



The number of varieties of sugar eane {SaccMnim officinarum) 

 is increasing rapidlj^,* and for tliis reason it is desirable to have a 

 method of describing and identifying them. In some cases the points 

 of difference are easily seen, but usually this is not so. This may be 

 due to any of the following reasons: first, that there is a wide range 

 of variation within the varieties, so that, as a consequence, the type 

 is not represented in a single stalk, or in a single plant ; second, 

 that a large number of varieties tends to make the differences be- 

 tween some of them very slight; and third, that the differences are 

 ciuantitative variations of characters common to all, and not the 

 addition of definite new characters. The distinguishing marks are not 

 always found on all the stalks. The type is in many cases difficult 

 to determine, and although two varieties grown side by side may be 

 seen to be distinctly different, it is not always easy to state wherein 

 the dift'erences lie. 



Cane varieties vary widely in economic characters as well as in 

 appearance. These characters are yield of cane, sugar content, mill- 

 ing quality, resistenee to diseases, resistence to unfavorable condi- 

 tions for growth, and so forth. Some varieties are much better suited 

 to certain localities than others, and in Porto Rico it may be said that 

 the four kinds of cane extensively cultivated are most connnonly 

 grown in more or less well-marked regions. This seems to be largeh' 

 due to soil and climatic conditions, although it is difficult to state defin- 

 itely, in every case, the exact factors which control their distribution. 



THE PARTS OF THE SUGAR-CANE PLANT. 



The sugar cane belongs to the grass family, or Gramiueac, sub- 

 family Poacoideac, tribe Andropogoneae, and genus Saccharuni. The 

 stems are unbranched and solid. The leaves are alternate and are 



* The increase in the numbei- of varieties is a result of breeding, conducted for the 

 purpose of securing superior kinds. Tliis is being: done in practically all caneproduc- 

 ing countries. It was commenced in .Tava in 1887 and in the British West_ Indies in 

 1888, and was taken up on account of the advance made by the sugar beet industry in 

 competition, and an apparent deterioration of the standard varieties of cane. 



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