Growth and Radiation Use Efficiency of Sugarcane Under Irrigated and Rain-fed Conditions in Sri Lanka

Abstract

A field experiment was conducted to evaluate sugarcane varieties based on their radiation use efficiencies (RUE) at the Sugarcane Research Institute, Uda Walawe, Sri Lanka. Sugarcane was grown under irrigated (soil water potential >−0.05 MPa) and rain-fed conditions in a split-plot design. Biomass accumulation, canopy development, leaf angle and radiation intercepted by the sugarcane canopy were measured. Seasonal and fractional incoming radiation intercepted, light extinction coefficient (k) and RUE were estimated. Rain-fed crop reduced RUE by 53 % compared to the irrigated crop. RUE varied from 1.63 to 2.09 g MJ−1 and 0.71 to 1.03 g MJ−1 under irrigated and rain-fed conditions respectively. The variety SL 83 06 showed the highest RUE under both water regimes with higher canopy development and lower k values consistently throughout the growing period. The canopy in erect leaves increases biomass production and RUE. As the erect orientation of leaves is genetically governed trait, it could be used for the hybridisation programme of sugarcane to produce highly efficient solar energy-utilising hybrids of sugarcane.