• 作者： 吳大本
• 作者服務機構： 台灣大學植物系
• 中文摘要： 分析比較蜀黍的五個亞屬之十五個物種的外部形態特徵知Eu-sorghum, Heterosorghum和Chaetosorghum三亞屬間之親緣關係密切，可組成一類，而Stiposorghum和Para-sorghum二者親緣關係較密切，構成另一類。分析比較此等材料之粗絲期核型表示Heterosorghum（2n＝40）和Chaetosorghum（2n＝40）之核型與Eu-sorghum者頗相似，但前二亞屬之染色體數各為Eu-sorghum（2n＝20）者之兩倍。由此等形態及核型之觀察，吾人推測無論Heterosorghum或Chaetosorghum可能皆源自二Eu-sorghum之物種（2n＝20）經自然雜交再行染色體加倍而成之異質多倍體。在Eu-sorghum之Halepensia節中也可發現其他異質多倍體物種，而同質多倍體物種則僅存在於Stiposorghum和Para-sorghum二亞屬中。除核仁染色體不同外，Stiposorghum和Para-sorghum二者核型基本相似，反之該二亞屬之核型與Eu-sorghum者完全不同。故就核型演進途徑而言，不可能由Stiposorghum及Para-sorghum產生Eu-sorghum，反之亦然。
• 英文摘要： The taxonomic characters of fifteen species including all five subgenera of sorghum were studied. Thesetaxonomic data clearly suggest that subgenera Eu-sorghum, Heterosorghum and Chaetosorghum make upone circle of morphological affinity, and that subgenera Stiposorghum and Para-sorghum compose anothercircle of morphological affinity. Detailed analyses and comparisons of the pachytene karyotypes of thesematerials show that the karyotypes of Heterosorghum and Chaetosorghum are essentially similar to that ofEu-sorghum, except for a difference in chromosome number; the former two have twice the chromosomenumber of the 20-chromosome Eu-sorghum. Based on morphological and cytological observations, we specu-late that Heterosorghum and Chaetosorghum are allopolyploids that arose from chromosome doubling ofhybrids between putative 20-chromosome Eu-sorghum species. Other allopolyploids are also found in thesection Halepensia of the Eu-sorghum whereas the autopolyploids are apparently restricted to Stiposorghumand Para-sorghum. There is no basic difference between the pachytene karyotypes of Stiposorghum andPara-sorghum with the exception of the nucleolar chromosome. On the contrary, the pachytene karyotypesof these two subgenera are completely different from that of Eu-sorghum. Therefore, it seems logical toconsider that the genus Sorghum may be separated cytologically into two different architypes. One with basicnumber x = 5 includes Stiposorghum and Para-sorghum, and the other with basic number x = 10 contains Eu-sorghum, Heterosorghum and Chaetosorghum. Complete differences in chromosome morphology are foundbetween species of these two architypes, which suggests that Stiposorghum and Para-sorghum have played norole in the evolution of the karyotype in Eu-sorghum.
• 中文關鍵字： cytotaxonomy; karyotype analysis; Eu-sorghum; Chaetosorghum; Heterosorghum; Stiposorghum; Para-sorghum.
• 英文關鍵字： --