BUD VARIATION IN THE SUGAR 



CANE 



E. Eugene Barker 

 Insular Experiment Station, Rio Piedras, Porto Rico 



LIKE other crops extensively cul- 

 tivated by asexual methods, 

 the sugar cane is subject to much 

 variation. During the several hundred 

 years in which it has been cultivated 

 it has given rise, literally, to thou- 

 sands of varieties. In the recent period 

 of deliberate efforts to produce new- 

 sorts, many seedling varieties have 

 been secured which are distinguished 

 by characters more or less marked. 

 However, it is the phenomenon of bud 

 variations in the sugar cane, to which 

 it is wished to call attention in this 

 paper. 



First, however, in order to show 

 the actual range of variation in this 

 plant, as regards a few of its economic 

 characters, let us cite several examples, 

 regardless of how they may have 

 originated. 



FACTORS INFLUENCING YIELD 



Sucrose content of the juice, which, 

 together with gross yield in tonnage, 

 determines the value of the crop, varies 

 greatly in the different varieties. 

 To be sure, this is supposed to be 

 influenced by the climatic conditions 

 and the soil, but there are strongest 

 indications that the real immediate 

 factor is maturity as conditioned by 

 the age of the cane. After all, it is a 

 varietal difference, as some varieties 

 have the ability to produce sugar 

 early before they are mature, while 

 others sweeten later. We might call 

 this varietal adaptability to produce 

 sugar at a given age as conditioned 

 by climatic and edaphic factors. 

 Thus, while these environmental con- 

 ditions are determining factors, they 

 are probably only secondarily so as 

 working upon the constitution of the 

 variety itself. 



This matter of varieties suited to 

 different soil types is one to which 



little attention has been given, and 

 yet it is a factor of greatest importance 

 to the agriculturist. In a recent test 

 of varieties at the Insular Experiment 

 Station in Porto Rico, certain vari- 

 eties were chosen which, it was sup- 

 posed, might be best suited to the type 

 of soil known as red clay hill lands. 

 These were planted together and at 

 the same time in a field of this type 

 on the station farm. At 14 months- 

 from planting analyses show a great 

 range of variation in the characters- 

 of sucrose content and purity of juice. 

 Here, close together in the same 

 field and raised under identical con- 

 ditions, variety D-208 gives juice of 

 18.40% sucrose and 94.84% purity, 

 others closely following, while B-4596 

 is only 13.65% sucrose with 85.31% 

 purity and Gigante is 12.32% sucrose 

 with 77.00% purity. It is apparent 

 also, that there is great variation ia 

 tonnage amongst these varieties grow- 

 ine here. 



STRIKING VARIETAL DIFFERENCES 



This planting serves to show_ three 

 things: (1) the range of variation in 

 important economic characters,^ (2) 

 the relative adaptability of varieties 

 to different soil types, and (3) in 

 connection with other analyses made 

 month by month, that some varieties 

 mature early and others later. This 

 last fact is one wholly ignored at the 

 present time by the farmers and man- 

 agers of large centrals. Fields are 

 mixed as to varieties and canes are 

 planted and cut regardless of variety 

 or seasonal maturity. 



As to differences in resistance to 

 disease, there are many noteworthy 

 examples. Yellow Caledonia and Cav- 

 vangire and Demerara -625 resist the 

 so-called "root-disease" comparatively 

 well, while Otaheite and many others 



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