A study on the effect of altitude and harvesting dates (HD) on plant morphological characteristics, yield, and chemical composition of Desho grass (Pennisetum pedicellatum Trin.) was carried out during 2015/2016 under irrigation at Mecha (mid altitude) and Farta (high altitude) districts, northwestern Ethiopia. The objective of the study was to determine the optimum harvesting date (HD) and suitable altitude for maximum biomass yield and better nutritional value of the Desho grass. The harvesting dates used in the study were 75, 105 and 135 days after planting. Furrow irrigation was employed throughout the experimental period. The experimental design employed was factorial design with two factors altitude (mid and high) and HD (75,105 and 135) with three replications consisting of 6 plots in each block/replication. The morphological data collected from were plant height (PH), number of tiller per plant (NTPP), number of leaves per plant (NLPP), number of leaves per tiller (NLPT), and leaf length per plant (LLPP). Chemical composition data such as crude protein (CP), organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) were analyzed and forage dry matter yield per hectare was quantified. Plant characteristics such as PH, NTPP and NLPT were significantly (P< 0.001) affected by altitude and HD. The higher PH, NTPP, and NLPT were recorded for Mecha district (mid altitude) location with increasing trends of HD. HD significantly (P<0.001) affected the NLPP, LLPP and biomass yield; with highest value recorded at 75, 105 and 135 dates, respectively. Chemical composition parameters were not significant (P>0.05) by altitude but CP, NDF and ADF were significant (P<0.001) by HD; the highest value recorded at 75, 135 and 135 dates, respectively. Pearson correlation analysis showed that PH was significantly (P<0.01) and positively correlated with majority of plant characteristics. Overall, from the harvesting dates, the intermediate HD (105 day) could be selected for better CP without compromising the biomass yield as far as this experiment is concerned. Therefore, it can be concluded from the study that Desho grass could be produced substantially both in high and mid lands as long as irrigation scheme are available.
