Two field experiments were conducted at El-Gemmeiza Farm, Agricultural Research Center, during 2022 and 2023 seasons to study three forage crops (millet, sudan grass and teosinte) under six levels of recommended mineral nitrogen fertilizer (RMNF) beside grain inoculation with cerealin biofertilizer (bio) on growth characters, dry matter accumulation, forage productivity and quality as well as correlation coefficient between fresh forage yield/fed and all previous characters.- The averages of three cuts, millet crop were superior to sudan grass and teosinte crops in no. of tillers and leaves/plant, leaves area, dry weights of leaves, stem and total/plant as well as fresh and dry yields/fed. However, sudan grass surpassed the rest crops in plant height. Meanwhile, Teosinte crop exceeded in protein and digestible protein% in both seasons. - Application of 100% RMNF + bio (T5) recorded the highest significant values for all studied traits compared to the other tested N fertilization treatments during the two growing seasons. However, there were no significant differences between 75% RMNF+ bio(T4)and100%RMNF + without bio (T6) for all the studied traits in the three cuts during the two growing seasons.-The interaction between the two tested factors indicated that the application of T5 generally recorded the highest values for most characters studied in the tested crops in one or more cuts in both seasons.-There were a positive and high significant phenotypic correlation between fresh forage yield/fed and all growth characters, dry matter accumulation and dry forage yield/fed as well as CP% and DCP% mostly in the three forage crops.