(53(3):165-178)The Study on Genetic Diversity of the Core Collection for Capsicum Using Random Amplified Polymorphic DNA

本研究之主要目的為針對利用性狀調查資料所建立的番椒屬種原核心收集，期望藉由RAPD分子標記，就分子層次瞭解該種原核心收集的遺傳歧異結構。本研究以16個逢機引子，針對番椒屬種原核心收集的264份種原進行RAPD分析，並據此進行集群分析結果發現，由兩群間最小距離 (Mini Distance; MD) 於0.83為分群依據時，可明顯的將番椒屬種原核心收集區分為5個子群，其中C. annuum 的種原有92％集中在第1子群，C. baccatum 亦有92％的種原集中在第4子群，C. chinense 的種原為86％集中在第2子群，C. frutescens 為86％的種原集中在第3子群，而C. chacoense 則是全部的參試種原皆集中於第5子群，顯示就分子層次而言，番椒屬內各不同“種”別的種原間具有顯著的遺傳歧異，因此在建立番椒屬種原核心收集時，應以儘量包含不同“種”別的種原為考量。針對同一“種”別之種原研究結果發現，仍有少部份的種原會散佈至其它子群中，顯示“種”內亦具有相當程度的歧異分化存在，以保存寬廣之遺傳歧異的觀點而言，這些具有歧異分化的種原納入在種原核心收集中是相當有意義的。經由 Shannon-Weaver 歧異指數之估算發現，第1子群（主要成員為C. annuum）歧異指數較低（為0.783），顯示群內種原間的遺傳相似性較其它群為高，研究認為應可藉由RAPD分子標記針對該群種原進行再篩減，以形成更具代表性的種原核心收集。因此本研究應用RAPD分析探討番椒屬種原核心收集之結果顯示，藉由分子標記不但有助於瞭解分子層次的遺傳歧異結構，並可應用於輔助種原核心收集之建立。The objective of this study was to evaluate the genetic diversity of Capsicum core collection by RAPD. The core collection which contains 264 accessions of Capsicum spp. was constructed with 12 ratio scale traits. The cluster analysis based on RAPD from 16 random primers showed the accessions of core collection could be divided into 5 clusters as the mini distance (MD) was greater than 0.83. Most (92%) of the C. annuum were assembled in cluster 1, 92% of the C. baccatum were in cluster 4, 86% of the C. chinense were in cluster 2, 86% of the C. frutescens were in cluster 3, and all of the C. chacoense were in cluster 5. Cluster analysis revealed there are obvious molecular diversity among species within Capsicum. Therefore, it is recommend that the Capsicum core collection should cover the germplasm from different species as many as possible. For the accessions from the same species, there are still some scattered to the other clusters. The result showed certain of molecular diversity existed within species. Aimed at the viewpoint to conserve broad genetic diversity, these distinct germplasm should be included in core collection. The Shannon-Weaver diversity index of the cluster which primarily composed of C. annuum was 0.783, which revealed there are higher similarity within this cluster. The accessions within the cluster could be reduced by way of RAPD analysis. This study showed the RAPD molecular markers not only provided insights into the genetic structure, but also assisted the construction of core collection for Capsicum