Assessment of Sorghum bicolor fodder attributes for agroclimatic potential under salt stress

Sorghum (Sorghum bicolor L.) is mainly produced as an infallible crop in semi-arid and arid areas. Though the impact of salinity on crop production is extensively documented, very limited studies are available demonstrating the interaction between fodder quality and irradiance use efficiency in sorghum. To study such interactions, the present study aimed to evaluate the resource use efficiency in different sorghum lines for fodder evaluation under a varied salinity regime (60 to 120 mM NaCl), on the 2017-18, 2018-19 and 2019-20 kharif seasons. Sorghum grown on June 15, 2018employed higher thermal and heat units than July 2, 2019. Sorghum genotypes' differential quality and yield responses to various temperatures were due to differences in high salinity tolerance during various growth stages. The crop sown on June 15th required the most growing degree days units to reach various phenological stages and physiological maturity. SSG 59-3 maintained higher crude protein, in vitro dry matter digestibility (IVDMD), crude protein yield, and digestible dry matter at 120 mM NaCl. SSG 593 exhibited maximum green fodder yield (GFY) and dry matter yield (DMY), while PC-5 had the minimum. SSG 59-3 genotype accumulated high radiation use efficiency (281.23 kgha-1 MJ1), heat susceptibility index (0.42%), and yield stability ratio (87.2%) in both control and stressed environments, while PC-5 showed moderate tolerance to temperature stress and thus recorded a lower heat susceptibility index. Since there is no discernible correlation between the agronomic and fodder quality factors, it is possible to breed for desired qualities using independent associations. The results showed that the SSG 59-3 genotype adopted optimum allocation of resources for biomass production, maximized yield potential, and could be utilized in breeding programs as a potential fodder crop in saline regimes.