臺灣甘藷野生近緣種收集及其分布

Abstract

甘藷為原產於熱帶美洲的旋花科植物，本省地處亞熱帶，就地理環境而言，非常適於甘藷栽培“由於野生旋花科植物的外形相似，不易鑑別親緣關係，實有必要詳加研究，以期能確實掌握野生種源，提供進一步的育種運用。 臺灣的旋花科植物依其形態特徵，可分成14屬58分類群，其中美麗銀背藤、天茄兒、雍菜、甘藷、樹牽牛、葵葉蔦蘿、牽牛花、蔦蘿、白花鳶蘿、巴西牽牛、多裂魚黃草、木玫瑰及金魚花等種類為引進的栽培種外，其餘分類群散見於全省各地平野，遺傳資源相當豐富。 就其地理分布而言：本科植物大多分布在海拔700公尺以下的平野地區，同時以南部為主要分布中心；只有臺灣菟絲子、馬蹄金、土丁桂、白花牽牛、銳葉牽牛及紅花野牽牛等種類，可在海拔1500公尺生長；亦只有腎葉打碗花及變葉姬旋花等以北部為主要分布中心。 又就其生態環境而言：本科植物為好陽性植物，只有白鶴藤、亨利氏伊立基藤、掌葉牽牛及圓萼牽牛等可在森林邊緣出現，而腎葉打碗花、馬鞍藤及厚葉牽牛等為典型的沙灘植物。 Sweet potato, a plant species native to tropical America, belongs to the family of Convolvulaceae. Including 15 introduced species, 14 genera and 58 taxa of this family have been recorded in Taiwan. The abundant gentic resources are considered of pivotal importance in the task of varietal improvement of sweet potato. Most sweet potato-related wild species are found under 700-m elevation and are common in the southern part of Taiwan. The exceptions are Casacia japanica var. forniosana, Dichondra micraniha Evalvulus alsinoides, Iponioea biflara, I. indica, and I. triloba which are also recorded in regions of 1,500 m in elevation. Calystegia soldanella and Merremi hirita are found only in the northern part of Taiwan. In terms of growing habitat, most species grow well in areas facing the sun. However, Argyreia acuta, Erycibe henryi I. digitata and I. staphyuina could also be found in margins of forest. In addition, Calystegia soldanella, I. pes-caprac, and I stoloaifera are observed frequently on coastal beaches.