178 STUDIES IN INDIAN SUGAECANE SEEDLINGS. 



THICKNESS OF CANE AND SUCROSE. 



Correlation 4. 



The method of measuring the thickness of the cane has undergone a 

 ffood many changes before a satisfactory one has been hit u])on. At first ten 

 or more canes were laid out and measured at the base, at the middle and at 

 the highest mature joint (judged by hardness of rind). Measurements were 

 also taken in two directions, namely, in the plane of the buds and at right angles 

 to it. The latter, however, was soon discarded as, in reality, merely a measure 

 of the ovalness in section, inherent in all sugarcanes. But these measure- 

 ments even then were altogether too cumbrous in any large series and, after 

 some changes, the following plan was adopted. All the canes of a seedling 

 at crop time were laid out on a table and an average one was selected by eye 

 measurement. This was then measured by calipers at the middle in the plane 

 at right angles to the line of buds. The correlation is thus between the 

 thickness of an average cane at middle and sucrose in the juice. The results 

 are conflicting, and possibly no true correlation exists. But, in thegenei-al 

 series, there is a somewhat marked negative tendency in most cases. The 

 crosses, on the other hand, and Naanal, show the opposite tendency, namely, 

 to a positive correlation. This may be in accordance with the fact that the 

 thick stennned parent is vastly richer in sucrose tluin the wiltl form with 

 which it has been crossed. On the whole, beyond these tendencies, no 

 definite correlation can be said to have been established between cane 

 thickness and sucrose. 



