Abstract

All sugarcane growers are aware of the occurrence of pith in some sugarcane varieties. The pith usually commences from the central region of the sugarcane. Histologically, pith-formation proceeds by the loss of cell-sap and drying up of the innermost tissue of the central cylinder, and the magnitude of pith formed varies from a central streak or fistular strand to the entire region becoming dry and corky. The natural causes of pith-formation are believed to be either varietal or due to deterioration-phases commonly attendant on over-maturity. In any case, it is of primary importance to the sugarcane grower to know when pith- formation forms in a particular variety, and how far it develops with time, to enable the choice of the right variety and to fix upon the most beneficial time of harvest. Moreover, pith-formation is an economic loss to the grower, as it saps the juice and reduces cane-weight resulting in the loss of cane tonnage. A study of the commencement and relative progress of pith formation in different varieties of sugarcane is of great value in preventing loss of cane out-turn, a factor of vital interest to the grower. So far the only method of estimating pith-formation consisted in cutting open the cane, and examining the longitudinal and transverse sections for pith formed. Such qualitative observations, although affording a clue, could never be so precise or exact as quantitative determinations. The enunciation of a suit- able quantitative technique engaged the serious attention of the senior author of this paper, and the method of density determinations described hereunder, proved to be a reliable means of estimating the relative degrees of pith formation in canes. As a natural consequence of pith formation the cane becomes light, and the volume remaining the same, the density is consequently lowered.

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