Sugarcane leaf area development under field conditions in Florida, USA

Leaf area development is critical in the establishment of a full leaf canopy to maximize interception of solar radiation and achieve high crop productivity. In sugarcane, leaf area development is especially important because the rate of leaf area increase is relatively slow. Previous studies have highlighted the fact that the rate of emergence of individual leaves is highly dependent on temperature. These previous studies have been limited, however, to only very few cultivars, and these cultivars were adapted for production in environments different from the climate of the continental USA. Hence, there is little information for cultivars selected for production in other environments and little basis for resolving which variable contributing to leaf area development has the greatest impact on canopy leaf area. The objective of this 2-year field study was to examine the contribution of rate of leaf emergence, leaf shape, and individual leaf area to the development of plant leaf area. Four cultivars developed for the subtropical climate of Florida were compared. The dependence of leaf emergence as a function of temperature was confirmed in this study and the leaf appearance rate of CP88-1762 was significantly greater than CP72-2086. Leaf shape was found to be nearly uniform among the four cultivars although the shape factor (0.72) was different from that previously reported for sugarcane. Cultivars differed in the area of successive emerged leaves on the stalk. Leaves produced early in development were found to be larger for one cultivar (CP88-1762) as compared to the other cultivars. These results indicated that area of earliest leaves produced by sugarcane cultivars might be a variant that could be exploited to achieve more rapid development of crop leaf area. (C) 2004 Elsevier B.V. All rights reserved.