Unique Salt-Tolerance-Related QTLs, Evolved in <i>Vigna riukiuensis</i> (Na<sup>+</sup> Includer) and <i>V. nakashimae</i> (Na<sup>+</sup> Excluder), Shed Light on the Development of Super-Salt-Tolerant Azuki Bean (<i>V. angularis</i>) Cultivars
Eri Ogiso-Tanaka,
Sompong Chankaew,
Yutaro Yoshida,
Takehisa Isemura,
Rusama Marubodee,
Alisa Kongjaimun,
Akiko Baba-Kasai,
Kazutoshi Okuno,
Hiroshi Ehara,
Norihiko Tomooka
Affiliations
Eri Ogiso-Tanaka
Genetic Resources Center, National Institute of Agrobiological Sciences (NIAS), 2-1-2 Kannondai, Tsukuba 305-8602, Ibaraki, Japan
Sompong Chankaew
Program in Plant Breeding, Faculty of Agriculture at Kamphaeng Saen, Kasetsart University, Kamphaeng Saen, Nakhon Pathom 73140, Thailand
Yutaro Yoshida
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennohdai 1-1-1, Tsukuba 305-8571, Ibaraki, Japan
Takehisa Isemura
Genetic Resources Center, National Institute of Agrobiological Sciences (NIAS), 2-1-2 Kannondai, Tsukuba 305-8602, Ibaraki, Japan
Rusama Marubodee
Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu 514-0102, Mie, Japan
Alisa Kongjaimun
Genetic Resources Center, National Institute of Agrobiological Sciences (NIAS), 2-1-2 Kannondai, Tsukuba 305-8602, Ibaraki, Japan
Akiko Baba-Kasai
Genetic Resources Center, National Institute of Agrobiological Sciences (NIAS), 2-1-2 Kannondai, Tsukuba 305-8602, Ibaraki, Japan
Kazutoshi Okuno
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennohdai 1-1-1, Tsukuba 305-8571, Ibaraki, Japan
Hiroshi Ehara
Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu 514-0102, Mie, Japan
Norihiko Tomooka
Genetic Resources Center, National Institute of Agrobiological Sciences (NIAS), 2-1-2 Kannondai, Tsukuba 305-8602, Ibaraki, Japan
Wild relatives of crops have the potential to improve food crops, especially in terms of improving abiotic stress tolerance. Two closely related wild species of the traditional East Asian legume crops, Azuki bean (Vigna angularis), V. riukiuensis “Tojinbaka” and V. nakashimae “Ukushima” were shown to have much higher levels of salt tolerance than azuki beans. To identify the genomic regions responsible for salt tolerance in “Tojinbaka” and “Ukushima”, three interspecific hybrids were developed: (A) azuki bean cultivar “Kyoto Dainagon” × “Tojinbaka”, (B) “Kyoto Dainagon” × “Ukushima” and (C) “Ukushima” × “Tojinbaka”. Linkage maps were developed using SSR or restriction-site-associated DNA markers. There were three QTLs for “percentage of wilt leaves” in populations A, B and C, while populations A and B had three QTLs and population C had two QTLs for “days to wilt”. In population C, four QTLs were detected for Na+ concentration in the primary leaf. Among the F2 individuals in population C, 24% showed higher salt tolerance than both wild parents, suggesting that the salt tolerance of azuki beans can be further improved by combining the QTL alleles of the two wild relatives. The marker information would facilitate the transfer of salt tolerance alleles from “Tojinbaka” and “Ukushima” to azuki beans.