生物多樣性公約 人類共同遺產 無主物 公有物 植物遺傳資源國際承諾書 糧農植物遺傳資源國際條約 Convention on biological diversity CBD Common heritage of mankind CHM Res nullius Res communes International undertaking on plant genetic resources IUPGR International treaty on plant generic resources for food and agriculture APGR