Assessment of genetic diversity in Sehima nervosum for yield, nutritional traits and ensiling quality

The low sugar content of tropical range grasses makes them difficult to ensiling. This study identified sugar rich (>7 % on dry matter basis) accessions of Sehima nervosum (SN), which is adequate to initiate lactic acid production during ensiling. Sehima is a prominent range grass of Sehima-Dichatnthium grasslands in India followed by Africa, Pakistan, China and Australia. In this study, 92 diverse SN germplasm accessions were evaluated for biomass yield, nutritional quality and sugar content. Green forage yield was higher in rainy season (ranged 2.2 to 58.1 t ha^-1) compared to post rainy season (varied between 0.48 and 44.0 t ha^-1). The approximates values expressed (%), crude protein ranged from 3.15 to 6.10, neutral detergent fiber from 67.13 to 81.95, acid detergent fiber from 42.03 to 56.05, cellulose from 24.49 to 37.98 and lignin from 3.78 to 7.97. Sugar content varied from 27.04 to 123.32 mg g^-1 DM. To advance this experiment, the next phase involved selecting 19 accessions of SN with >7 % sugar content on DM and promising forage yield. These accessions again evaluated for nutritional quality, subjected to in vitro tests, and then assessed for ensiling potential. Among 19 accessions, carbohydrate bound to lignin (Cc) ranged from 15.35 % to 25.63 % total carbohydrates. The total digestible nutrients (TDN) ranged from 33.07 % to 44.32 %, digestible energy (DE) from 1.46 to 1.95 Kcal per kg of dry matter (DM), and metabolizable energy (ME) from 1.20 to 1.60 Kcal per kg of DM. The intake of dry matter, digestible dry matter, and relative feed value varied from 1.55 to 1.77, 45.88 %-51.51 %, and 57.96 %-66.94 %, respectively. Methane production, as a percentage of the total gas, was at its lowest for IG-99-195 (7.91 %) and reached its highest for IG-01-391 (14.97 %). Silage pH ranged from 4.57 (IG-02-703) to 5.61 (IG-99-181) and lactic acid from 0.094 % to 1.774 % DM. Accessions IG-02-703, IG-02-713, and IG-2045-1 had good silage quality, with suitable pH and lactic acid levels. Planting these in pastures and grazing lands could improve the availability of quality fodder during lean periods.