Effects of Cultivar and Harvesting Age on Morphological Characteristics, Yield and Nutritive Values of Guinea Grass (Panicum maximum) Grown Under Irrigation Conditions in Different Locations of Western Amhara Region, Ethiopia Adebabay Adane1, Fentahun Meheret2 and Abule Ebro3 1Andassa Livestock Research Center, Amhara Agricultural Research Institute (ARARI), P.O. Box 27, Bahir Dar, Ethiopia 2College of Agriculture and Environmental Sciences, Bahir Dar University, P. O. Box 5501, Bahir Dar, Ethiopia 3Wageningen University and Research, BRIDGE Project, P. O. Box 40675, Addis Ababa, Ethiopia The study was conducted at Andassa Livestock Research Center and North Mecha districts in Western Amhara with objective of evaluating morphological characteristics, yield and nutritive values and identifies best adaptable Guinea grass (Panicum maximum) based on factors of cultivar and harvesting age under irrigation conditions. The experiment was laid in a randomized complete block design with a 3×3 factorial arrangement with three replications. The Panicum maximum cultivars were Mombasa, Tanzania and Degun gizia and harvesting ages were 60, 81 and 102 days after planting at Andassa and North Mecha locations. Panicum maximum was planted using vegetative root splits on a well-prepared land with spacing of 50 by 50 cm between rows and plants. The space between replicates and plots was 1.5 and 1m respectively. Agronomic managements such us hoeing, fertilizer application, irrigation and weeding were done manually. The morphological data were plant height, tiller number, number of leaves per plant, width and length of leaf, number and length of root and leaf-to-stem ratio collected and analyzed. The data also on dry matter yield, dry matter content, ash, crude protein, acid detergent fiber, neutral detergent fiber, acid detergent lignin, metabolizable energy, In vitro dry matter digestibility and in vitro organic matter digestibility were done. All collected data were subjected to a three-way analysis of variance (ANOVA) using the General Linear Model (GLM) SAS version 9.0 and Significant at (P<0.05) means were compared using Duncan Multiple Range Test. Analysis indicated that there were not significant interaction effects among harvesting age and cultivars of Panicum maximum for all studied morphological characteristics and chemical composition but leaf-to-stem ratio, dry matter yield, crude protein yield, digestibility and metabolizable energy values were observed interaction in the current study. The result indicated morphological characteristics, dry matter yield and nutritive values were affected significantly (P<0.05) by harvesting age and cultivars. At Andassa location, Mombasa had scored better values in most morphological characteristics, DMY (11.94t/ha), CPY, and fiber parameters while Tanzania scored CP (11.41%) with CPY; and Degun gizia cultivar exhibited better values on LSR, CP (11.47%) and digestibility content. At Mecha location also Mombasa scored better values on fiber parameters; Tanzania obtained CP (13.63%) and digestibility; Degun gizia also scored the highest values on LSR, CP (13.44%), fibers, DMY (9.84t/ha) and CPY. Early harvest age (60 days) resulted in the highest crude protein leaf-stem ratio, digestibility and energy while at late (102 days) high morphological characteristics and DMY. It was concluded that tested cultivars scored better dry matter yield and forage quality therefore use as an alternative forage resource for animals. Therefore, Panicum maximum cv. Mombasa and Tanzania were recommended at 81 harvesting ages in Andassa area while Mombasa and Degun gizia cultivars at 102 ages of harvest for Mecha and similar areas.