title: A Homoploid Hybrid Between Wild Vigna Species Found in a Limestone Karst.
abstract: Genus Vigna comprise several domesticated species including cowpea and mungbean, and diverse wild species. We found an introgressive hybrid population derived from two wild species, Vigna umbellata and Vigna exilis, in Ratchaburi district, Thailand. The hybrid was morphologically similar to V. umbellata but habituated in a limestone rock mountain, which is usually dominated by V. exilis. Analyzing simple sequence repeat loci indicated the hybrid has undergone at least one round of backcross by V. umbellata. We found the hybrid acquired vigorous growth from V. umbellata and drought tolerance plus early flowering from V. exilis, and thus has taken over some habitats of V. exilis in limestone karsts. Given the wide crossability of V. umbellata, the hybrid can be a valuable genetic resource to improve drought tolerance of some domesticated species.
authors.affiliation: Genetic Resources Center, National Institute of Agrobiological Sciences Tsukuba, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Genetic Resources Center, National Institute of Agrobiological Sciences Tsukuba, Japan.
authors.forename: Kohtaro
authors.initials: K
authors.lastname: Iseki
authors.affiliation: Department of International Agricultural Development, Tokyo University of Agriculture Tokyo, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Kitazawa
authors.affiliation: Genetic Resources Center, National Institute of Agrobiological Sciences Tsukuba, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Muto
authors.affiliation: Department of Agronomy, Faculty of Agriculture at Kamphaeng Saen, Kasetsart University Nakhon Pathom, Thailand.
authors.forename: Prakit
authors.initials: P
authors.lastname: Somta
authors.affiliation: Department of International Agricultural Development, Tokyo University of Agriculture Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Irie
authors.affiliation: Genetic Resources Center, National Institute of Agrobiological Sciences Tsukuba, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Naito
authors.affiliation: Genetic Resources Center, National Institute of Agrobiological Sciences Tsukuba, Japan.
authors.forename: Norihiko
authors.initials: N
authors.lastname: Tomooka
keywords: drought tolerance; genetic resource; genus Vigna; homoploid hybrid speciation; introgressive hybridization; natural hybrid; stress tolerance; wild crop relatives