Mapping Genetic Diversity in Taro (C. esculenta) to Test Domestication Models

2021 Fiscal Year Final Research Report

• Project/Area Number: 17H04614
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 海外学術
• Research Field: Science in genetics and breeding
• Research Institution: National Museum of Ethnology
• Principal Investigator: Matthews Peter 国立民族学博物館, 超域フィールド科学研究部, 教授 (70281590)
• Co-Investigator(Kenkyū-buntansha): 池谷 和信 国立民族学博物館, 人類文明誌研究部, 教授 (10211723)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: Araceae / Colocasia / C. esculenta / C. spongifolia / domestication / chloroplast genome / wild taro

Outline of Final Research Achievements

Wild populations of taro (Colocasia esculenta) and other wild Colocasia species were mapped in Bangladesh, China, India, Japan, Malaysia, Thailand, and Vietnam. Nuclear and chloroplast loci were sequenced. Three evolutionary clades (CI-CIII) were found in the newly surveyed areas. Wild CIII taros are widespread in China, Vietnam and Thailand, and absent in Bangladesh. In Bangladesh, only CI wild taros were found, including subclades close to cultivated CI taros. A new species, C. spongifolia (Matthews et al. 2022), was found in China and Vietnam. Complete chloroplast genome sequences were analysed in six Colocasia species. Taro is clearly polyphyletic, with cultivated taros confined to Clades I and II. Wild CIII taro may be a distinct species, or a hybrid produced by ancient chloroplast capture from a different wild species in Southeast Asia.

Free Research Field

民族植物学　先史学

Academic Significance and Societal Importance of the Research Achievements

この研究の結果、ガンジス川とブラマプトラ川の流域とデルタは、熱帯湿地サトイモ（CI）の一次栽培化の有力な候補地域であり、C. formosanaはC. esculentaと明確に別種であり、インドから中国、ベトナムまでの東南アジア山岳地域は、サトイモ属の種多様性の中心であることが確認された。また、熱帯アジアの低地におけるCIIの野生サトイモの不在は、日本のCIIの栽培品種がヒマラヤの山地で生まれたというこれまでの指摘と矛盾しない。本研究は、育種家が進化の歴史を参考にして育種材料を選択できるようになる点で重要である。また、日本に存在するサトイモの多様な進化的・地理的起源も明らかにした。