This study was designed to systematically investigate the effects of different hybrid Pennisetum varieties and microbial additive treatments on the silage quality of hybrid Pennisetum. A total of six hybrid Pennisetum genotypes were employed， with each genotype assigned to a control group （CK）， Lactobacillus paracasei （LP） group， Bacillus subtilis （BS） group， and Lactobacillus paracasei + Bacillus subtilis （LP+BS） group. The inoculation dosages for both L. paracasei and B. subtilis were standardized at 1×10⁶ CFU·g^-1 fresh weight （FW）. Following a 30-day fermentation period， nutritional parameters and fermentation indices were quantified， with comprehensive evaluation conducted via Flieg scoring system and principal component analysis （PCA）.Results demonstrated that probiotic amendments significantly enhanced crude protein （CP） content in‘PI_587000’and‘536321’genotypes， while markedly reducing neutral detergent fiber （NDF） content in ‘536321’and‘103’genotypes. Supplementation with LP and LP+BS notably decreased the ammonia nitrogen ∶ total nitrogen （NH₃-N∶TN） ratio in‘Sunongke No.2’‘ 536321’‘102’and‘103’ （P<0.05）， whereas all BS-treated groups exhibited significantly higher NH₃-N∶TN ratios than LP+BS treatments （P<0.05）. Genotypes‘102’and‘103’showed elevated lactic acid （LA） accumulation. Integrative analysis of Flieg scores and NH₃-N∶TN ratios indicated that ‘late-maturing Pennisetum’displayed optimal fermentation performance， with LP+BS demonstrating the most pronounced improvement in forage silage quality. PCA yielded five principal components with a cumulative contribution rate of 86.558%， confirming‘late-maturing Pennisetum’as the top-performing genotypes and LP+BS as the most effective additive treatment. Conclusively，‘late-maturing Pennisetum’is preferable as silage substrate for hybrid Pennisetum， and the LP+BS consortium represents the optimal probiotic additive for enhancing silage quality.

Pennisetum americanum×P.purpureum  /  silage quality  /  Lactobacillus paracasei  /  Bacillus subtilis