自台灣15 個縣市收集104 個野外收集之狼尾草(Pennisetum purpureum)收集系樣品，調查分糱數、叢重等共16 個農藝性狀，以Statistica 7.0 程式分析農藝性狀間之相關係數，並進行群叢分析。結果顯示，狼尾草農藝性狀之株高與節間長、莖徑長與莖徑寬呈正相關，相關係數分別達0.99 及0.98；乾物率與莖徑長、莖徑寬呈負相關，分別為-0.72 及-0.69。以15 個縣市為單位，將農藝性狀進行歸群之群叢分析，各縣市收集系之遺傳距離介於43 至4120 間，於距離500 點為截點則將收集系歸為5 群，分別為第1 群：宜蘭；第2 群：高雄、雲林、彰化、台中、屏東、桃園；第3 群：花蓮、嘉義、南投；第4 群：台南、台東、苗栗、新竹及第5群：台北。藉由狼尾草之種原樣品分群，可將台灣野生狼尾草粗略分為5 群，對於生態調查或評估，可於此5 處評估即可，但若須育種之選拔仍須搭配較精密之分子技術分群，較可縮短選拔時間。

Napiergrass (Pennisetum purpureum) is a perennial forage grass widely distributedgrown in Taiwan. A total of 104 samples of napiergrass samples were collected from 15counties in Taiwan. Cluster analysis was conducted based on 16 agronomic traits ofnapiergrass collections and correlation coefficients between agronomic traits weredetermined with Statistica 7.0 program. The objectives of this study were to investigatethe differences of agronomic traits and identify genetic variations by cluster analysis ofnapiergrass. The results showed that the correlation coefficients between plant heightand node height, stem diameter length (SDL) and stem diameter width (SDW) were0.99 and 0.98, respectively. Correlation coefficients between dry matter and SDL andSDW were -0.72 and -0.69, respectively. The genetic distance of napiergrass rangedfrom 43 to 4,120. All the 104 napiergrass collections were divided into 5 groups basedon the Euclidean distances 500 as the critical point. The 1st group was Eilan, the 2nd withKaohsiung, Yunlin, Changhua, Taichung, Pingtung and Taoyuan, the 3rd with Hualine,Chiayi and Nantou, the 4th with Tainan, Taitung, Miaoli and Hsinchu and the 5th withTaipei, respectively. It was suggested that napiergrass germplasms might be taken fromthese 5 groups for further ecology evaluation and select the elite lines for forage mightbe determined by Molecular technology.