Effect of Individual Leaf-Trimming on Flowering in Sugarcane

Abstract

The effect of individual leaf-trimming on sugarcane flowering is reported herein. Two varieties, N.Co. 310 and P.R. 980, were grown in the field under normal conditions of climate and nutrition. Individual leaf ranks were trimmed away twice (August 14 and 13) or once on September 1. It was shown that the expanding leaf and the leaf just fully expanded probably were most effective in producing the flowering stimulus. Greatest activity was found in the leaf —1 for N.Co. 310 and leaf 0 for P.R. 980. A significant depression in tassel emergence caused by the removal of leaf —2 and all the younger leaves within it may be related to the absence of leaf 0 which failed to appear in the normal replacement sequence during the critical period for primordia differentiation in P.R. 980. Both floral initiation and tassel emergence were increased by removing leaf 0, +1, or +2 in N.Co. 310. Selective defoliation was most effective when performed twice, on August 14 and 31. No significant effect on flowering was produced by removing an older leaf (+3 or +4), or a younger leaf (—1, P.R. 980, or —2, N.Co. 310), during the critical floral induction period.