Abstract:
Sugarcane suckers are tillers that appear late in crop development. They dilute the sucrose content of the harvested cane at the mill, reducing grower profitability. Suckers appear to have different morphology from other sugarcane stalks. Experiments were established to quantify some of these morphological differences, to determine whether these differences were conserved across a vegetatively propagated generation, and to investigate the influence of the mature stalk to which the sucker is attached on sucker morphology. Experiments were established in northern Queensland, Australia, using cvv. Q117, Q138, and Q152 to compare suckers with young primary stalks in a plant crop and/or young ratoon stalks. Leaf lamina length, breadth, area, height to last fully expanded leaf, internode diameter, and growth measurements were taken. Suckers had broader leaves, resulting in a smaller leaf length/breadth ratio, longer leaf sheaths, and lower specific leaf area at least for the first 3 leaves. Sucker stalks were thicker than normal stalks. Sucker growth was highly variable, but some were able to outgrow young primary stalks in a plant crop. When mature stalks, to which suckers were attached, were removed, the leaves produced by suckers were more similar to leaves on normal stalks with larger length/breadth ratio. The morphological differences were not carried over into plants arising from the buds on suckers. Although the reasons for these morphological differences are unknown, it is likely that the transfer of some factor(s) from the stalks to which suckers are attached, and/or an altered light environment within the canopy, may contribute to the morphology of sucker shoots.