Mushroom cultivation is a cost-effective biotechnological approach for converting diverse lignocellulosic wastes into nutritionally rich food. Hypsizygus ulmarius is a high yielding mushroom gaining popularity nowadays. In the present study the suitability of various available agro-industrial wastes and supplements for the cultivation of H. ulmarius was evaluated. Results indicated that among the seven locally available substrates, wheat straw substrate was found to be the best substrate as the highest yield (744.08 g/0.6 Kg dry substrate) and biological efficiency (124.00 %) were obtained. Number of sporophores was more in wheat straw substrate while stipe length was longest in pine needles and cap diameter was recorded maximum in maize straw. Moreover, yield was also recorded more in wheat straw supplemented with cotton seed hull significantly followed by the same substrate when added with gram flour and rice bran. However, lowest yield was obtained when no supplement was added in wheat straw. Bangladesh J. Bot. 52(1): 179-185, 2023 (March)

<i>Hypsizygus ulmarius</i>, a species with high biological efficiency, is multi-nutrient and is a medically good source of myco-chemicals. A study was carried out to evaluate different types of spawn to produce <i>H. ulmarius</i> utilizing various agroforestry wastes. Among seven different grain substrates evaluated, pearl millet grains were found to be the best substrate for spawn production as it supports much faster (11 d) and enhanced growth of <i>H. ulmarius</i>. A minimum period (13.67 d) was recorded for the complete spawn run, time taken for the first flush (20.33 d) along with the maximum number (38.33) of sporocarps produced in the wheat straw substrate. The longest stipe length (6.40 cm) was however, recorded in pine needles while the maximum (9.10 cm) cap diameter was found in maize straw substrate spawned with pearl millet grains spawn. Out of seven locally available substrates evaluated for production and yield parameters of <i>H. ulmarius</i>, maximum yield (640.00 g/0.5 kg dry substrate) having 128 percent biological efficiency was obtained when the wheat straw substrate was used significantly followed by wheat and maize grains spawn on the same substrate. Minimum time for spawn run, maximum number of sporocarps, maximum yield and biological efficiency was recorded in wheat straw substrate showing the best production substrate for <i>H. ulmarius</i> using pearl millet grains spawn. The results showed that agroforestry wastes can be alternatively used as potential substrates for cultivating <i>H. ulmarius. H. ulmarius</i> contain high amounts of proteins, carbohydrates, dietary fibers, unsaturated fatty acids, enzymes, and plenty of minerals among the commercially cultivated species. This mushroom has a good profile of vitamins, including B₁ (thiamine), B₂ (riboflavin), B₃ (niacin), A (retinol) and C (ascorbic acid), all of which are suitable for diet formulation and act as sources of energy.