Growth and yield of sorghum [Sorghum bicolor (L.) Moench] as affected by fertilizer levels and its cultivars

Abstract

A field experiment was conducted at Indian Institute of Millets Research, Hyderabad to evaluate the effect of fertilizer levels and cultivars on growth and yield of sorghum (Sorghum bicolor L. Moench). The study comprised four fertilizer levels based on the recommended dose of fertilizers (RDF): 0%, 50%, 100% and 150% RDF and three cultivars M 35-1, CSV 216R and CSH 15R. Results revealed that fertilizer application had a significant influence on plant height, drymatter accumulation, number of grains per panicle, grain yield, straw yield, biological yield and harvest index, while the number of panicles m-2 and test weight were not significantly affected. Application of 150% RDF produced the tallest plants (210.9 cm), which was on par with 100% RDF (203.7 cm), showing an increase of 19.3% over the control (170.2 cm). Similarly, the highest drymatter accumulation (132.3 g plant-1) was obtained with 150% RDF, followed by 100% RDF (126.6 g plant-1). Enhanced nutrient availability at higher fertilizer levels improved plant vigor, photosynthetic activity and biomass accumulation. Delay in days to 50% flowering (77.7 days) and maturity (126.6 days) with higher fertilizer level of 150% RDF was attributed to prolonged vegetative growth induced by nitrogen application. Among cultivars, M 35-1 recorded the highest plant height (207.4 cm) and drymatter (121.1 g plant-1), whereas hybrid CSH 15R flowered (74.5) and matured (120.0) earlier. Grain yield was significantly influenced by fertilizer levels, with the highest yield (3.68 t ha-1) recorded under 150% RDF, followed by 100% RDF (3.57 t ha-1), representing yield improvements of 40.7% and 38.9%, respectively, over the control (2.18 t ha-1). Similarly, straw and biological yields were highest under 150% RDF (8.59 and 12.27 t ha-1, respectively). Among cultivars, CSH 15R recorded the highest grain yield (3.27 t ha-1) and harvest index (30.8), while M 35-1 produced the highest straw (7.94 t ha-1) and biological yields (10.93 t ha-1).