Response of sweet sorghum genotypes for biomass, grain yield and ethanol production under different fertility levels in rainfed conditions

Abstract

Sweet sorghum (Sorghum bicolor (L.) Moench.) is a promising bio-energy crop and has potential to complement sugarcane production in diversified cropping systems. The objective of the present study was to assess the relative performance of advance open pollinated varieties (OPVs) for biomass, juice yield, quality traits, grain and bio-ethanol yields, and profitability under different fertility levels and locations. The performance of two advance OPVs (SPV 2074 and SPV 2075) was compared with check variety CSV 19SS and hybrid CSH 22SS under four fertility levels (80:40:40; 60:30:30, 40:20:20 kg N: P2O5: K2O ha−1 and control) at Indore (Madhya Pradesh), Pantnagar (Uttarakhand) and Palem (Andhra Pradesh). Treatments were replicated thrice in a factorial randomized block design . Plant height increased significantly (P B 0.05) with increasing fertility levels. Test genotype SPV 2075 had the tallest plant (290 cm). Application of RDF (80:40:40 kg NPK ha-1) reduced the number of days required for 50 % flowering by 3 days as compared to control. Test genotypes flowered 3 days earlier than the check CSV 19SS. Application of 80:40:40 kg NPK ha-1 increased the grain yield by 153 % over control and the test variety CSV 2074 produced 108 % higher grain yield than the check CSV 19SS. Fresh stalk yield, juice and potential ethanol yields were also increased with application of RDF. SPV 2074 and SPV 2075 produced higher juice yields as compared to check CSV 19SS. Juice yield was significantly (P B 0.01) and positively correlated with plant height (r = 0.667* *) and fresh stalk yield (r = 0.721* *). Maximum net returns (US $ 473.44 ha-1) and B: C ratio (2.09) were observed in plots treated with RDF (80:40:40 kg NPK ha-1). The test varieties SPV 2074 and SPV 2075 produced 93.8 and 56 % higher net returns as compared to check CSV 19SS.