Assessment climate change on Rabi grain sorghum (Sorghum bicolor (L.)

Sorghum (Sorghum bicolor (L.) Moench) is a climate-resilient cereal widely cultivated under rainfed conditions, yet its productivity remains highly sensitive to agronomic management and climatic variability. The present field experiment was conducted during the rabi season of 2024-25 at MPKV, Rahuri, to evaluate the interactive effects of sowing window, genotype and plant density on phenology, growth, physiological traits, biochemical stress responses, grain yield and fodder yield of sorghum. The experiment was laid out in a split-split plot design with three sowing windows (advanced, standard and delayed), ten rabi sorghum genotypes and two plant densities.

Results revealed that sowing window exerted a dominant influence on crop performance. The standard sowing window consistently prolonged crop duration, enhanced vegetative growth, improved canopy function and resulted in superior grain and fodder yields compared with advanced and delayed sowings. Delayed sowing significantly accelerated phenological development, reduced heat unit accumulation and intensified biochemical stress responses, as evidenced by higher proline content and peroxidase activity. Genotypic variability was pronounced across all traits, with genotypes such as Phule Suchitra and RSV-2832 exhibiting superior growth, physiological stability and yield potential, reflecting enhanced assimilate partitioning and stress tolerance. Plant density primarily affected per-plant performance, with reduced density improving individual plant growth and yield attributes, while plot-level yields were largely governed by population compensation.

Physiological traits, including relative leaf water content, SPAD values and thermal indices, closely aligned with observed growth and yield responses, underscoring the role of physiological homeostasis in sustaining productivity. Biochemical markers further confirmed increased stress under sub-optimal sowing conditions. Overall, the study demonstrates that optimal sowing time is critical for maximizing sorghum productivity, while genotype selection fine-tunes crop response within that window. Standard sowing combined with high-vigour genotypes such as Phule Suchitra offers a robust management strategy for enhancing grain and fodder yield under rainfed, climate-variable environments.