本研究主要目的於測定狼尾草(Pennisetum purpureum)品種：狼尾草臺畜草1、2、3 及4 號(cv. TLG1、cv. TLG2、cv. TLG3 及cv. TLG4)等4 個品種，進行淹水組(W)，即生長2 週、淹水2 週、再生長4 週，之完全逢機設計(complete randomized design, CRD)，於全生長期共8 週後，與對照組(CK)比較淹水對狼尾草之農藝性狀、單株鮮草產量及植物體成分之影響。結果顯示，第1 次淹水後，cv. TLG1、TLG2及TLG4 單株鮮草產量減少達顯著性差異(p<0.05)，但至第4 次淹水後4 個品種之單株產量與CK 產量均未達顯著性差異(p>0.05)。淹水對植物體成分之影響則至第2 次淹水後差異才顯示出來，不同品種淹水後粗蛋白質(crude protein, CP)含量較CK組低，水溶性碳水化合物(water soluble carbohydrate, WSC)濃度較CK 高。在各別品種間，cv. TLG3 受淹水之影響較不明顯，如第1 次淹水後產量僅降至CK 組產量之84%，但cv. TLG2 淹水後降至CK 產量之69%，且cv. TLG3 之CP 及WSC含量4 次淹水均未達顯著性差異。綜合上述，狼尾草第1 次淹水後，4 個品種之農藝性狀及單株鮮草產量除cv. TLG3 外，其餘品種都受到影響，但植物體成分則至第2 次淹水才達顯著性差異，狼尾草淹水後CP 含量會降低，WSC 含量則增加。各品種間以cv. TLG3 對淹水逆境較能適應，淹水後產量及植物體成分與CK 組差異不大。

The objective of this study was to determine the water tolerance of napiergrass (Pennisetum purpureum), including four cultivars, i.e., Taishu No.1 (cv. TLG1), Taishu No.2 (cv. TLG2), Taishu No.3 (cv. TLG3) and Taishu No.4 (cv. TLG4) unhder waterlogging stress. For the waterlogging treatment, two week-old plants were grown in waterlogging status for 2 weeks, and then were allowed to grow for another 4 weeks before harvest. The waterlogging treatment was conducted with 4 growth cycles within one year. All waterlogging experiments consisting of the complete randomized design (CRD)with 3 replications. The agronomic traits, fresh weight of single plant (FW) and chemical components of the plants were determined. The results showed that the FW of cv. TLG1, TLG2 and TLG4 decreased significantly (p<0.05) after 1st waterlogging. However, no difference of FW was observed between waterlogging treatment and CK after the 4th waterlogging. The chemical components of the plants were significantly affected by the 2nd waterlogging treatment. Crude protein (CP) in waterlogged plants was lower than that of CK and water soluble carbohydrate (WSC)was higher than that of CK after the 2nd waterlogging for 4 cultivars. The contents of CP and WSC for cv. TLG3 were not significantly afftected by waterlogging. The agronomic trait and the fresh weight of cv. TLG3 were less affected by waterlogging treatment. It suggested that cv. TLG3 was more tolerant to waterlogging than the other three cultivates.