Forage yield, proportions of morphological fractions and nutritive value of stay-green sorghum (Sorghum biochar L.) as affected by variety and growth stage

Five stay-green sorghum varieties (Chemeda, Gemedi, Asosa-1, Adukara and Marara) were evaluated at Bako Agricultural Research Center to determine the stover yield, morphological fractions and nutrient composition as influenced by variety and growth stages. A randomized complete block design with three replications was employed for the study, and data were analyzed using analysis of variance to determine significant differences among the factors. The trial was conducted over two years (2021 and 2022), ensuring a robust evaluation of varietal performance. The highest stover yield, plant height, and stem percentage were found in Chemeda and Gemedi, while Asosa1 and Adukara had higher leaf number, width, length, area, percentage, and leaf-to-stem ratio. Leaf number, percentage, and leaf-to-stem ratio decreased as plants matured, while stover yield, plant height, leaf width, length, stem percentage, and leaf area increased with plant growth. Crude protein, In-vitro dry matter and organic matter digestibility, and metabolizable energy traits were greater in the Asosa1 and Adukara varieties, but they tended to decline with the advancement in plant harvesting stages. Except for ash content which dropped with maturity, the dry matter, organic matter, neutral detergent fiber, acid detergent fiber, acid detergent lignin contents increased as plant harvesting time extended. Harvesting Asosa1 and Adukara varieties at the boot or bloom stage resulted in a lower stover output with a higher quality contents while harvesting Chemeda and Gemedi varieties after the hard dough stage typically generated higher quantities of lower quality stover. Therefore, the decision of end users to plant either variety will depend on their intended use for animal production and sorghum stover production potential. Future research should focus on assessing the performance of ruminant animals fed stover from either of the recommended sorghum varieties. • Chemeda and Gemedi varieties produced higher stover yield with lower quality • Asosa1 and Adukara varieties produced less stover yield of higher quality • Marara variety was lower in stover yield and quality features • Leaf attributes and leaf-to-stem ratio decreased as plants matured, while • Stover yield, height, leaf area, width, length, and stem percentage increased with growth • Cell wall components increased with maturity, while the reverse was true for cell contents.