Further Studies on the Role of Leaves in Sugarcane Flowering

Abstract

The role played by leaves in the perception and inhibition of the flowering stimulus was studied through defoliation treatment in three sugarcane varieties. It was found that the expanding leaves (0 and —1) in the variety P.R. 980 appear to be most effective in producing a flowering stimulus. The mature leaves (+3 and +4) in the variety Cl 41-223 appear to produce a transmissible flowering inhibitor. Absence of the young leaves within the leaf spindle during a period critical to initiation of inflorescence primordia resulted in a significant reduction of flowering intensity in varieties N.Co. 310 and Cl 41-223, and a marked delay in the flowering time in N.Co. 310. Removal of these leaves during subsequent stages of inflorescence caused a somewhat depressive flowering response and a considerable delay in the flowering time of N.Co. 310. A late-initiating variety, Cl 41-223 appears to begin producing a floral stimulus around August 20, about 2 to 3 weeks later than that of the early-initiating variety N.Co. 310.