Crop growth (accumulation of dry matter) depends mainly in the amount of intercepted radiation and the time allowed for growth (Sinclair and Muchow, 1999). The effectiveness of a crop to convert intercepted radiation to dry matter is called radiation use efficiency (RUE), and is defined as the amount of dry matter produced (g) per unit of radiation intercepted (MJ) by the crop canopy.
Variation is leaf shape range from highly divided leaves (okra leaf) to normal leaf shape (Meredith, 1984). Heitholt et al. (1992) described higher yields of okra leaf isolines for a given amount of intercepted radiation, indicating that the okra leaf types utilized more efficiently the intercepted radiation than the normal-leaf types. However, values of RUE for okra and normal leaf isolines have not been reported. Therefore research was conducted to compare the RUE of two cotton isolines with different leaf morphology.
