Radiation and Water use efficiencies of a Popular variety (SPV 462) and a Promising hybrid (CSH 14) of Sorghum under Semi arid climatic conditions of Hyderabad

This study was conducted to determine radiation and water use efficiencies of a popular variety (SPV 462) and a promising hybrid (CSH 14) of sorghum under semi arid climatic conditions of Hyderabad. The crop was sown in large plots with onset of sowing rains during 23–25 SMW (4–24^th June) in three years (2000–2002) of experiments. Recommended package of agronomic practices was followed. Leaf area, dry matter productivity and radiation interception were periodically recorded. The average extinction coefficients ‘k’ were 0.39 (R² = 0.87) and 0.46 (R² = 0.60) for the variety and the hybrid respectively. The ‘k’ coefficients were on par during the drought year but they were higher for the hybrid as compared to the variety during the normal years. The average radiation use efficiency was 3.69 and 3.48 (g MJ⁻¹) for the variety and the hybrid respectively during the three year period. The average water use efficiency was 3.71 and 3.18 g kg⁻¹ for the popular variety and hybrid. The radiation use efficiency (RUE) of the variety and the hybrid did not differ much during different years. But the water use efficiency (WUE) of the variety (2.66 g kg⁻¹) was higher than the water use efficiency (2.03 g kg⁻¹) of the hybrid during a drought year (2002).