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Wild Vigna [Vigna nakashimae (Ohwi) Ohwi & Ohashi]

Explanations

Taxonomy
Vigna nakashimae was formerly classified as a member of the genus Phaseolus or Azukia. Verdcourt(1970) proposed that this taxa should be transferred into the genus Vigna, subgenus Ceratotropis.
As for the taxonomy of Vigna, the taxonomic system of Marechal et al.(1978) was widely accepted now. However, V. nakashimae is listed as a species that was recognized by Verdcourt(1970), and examination based on the specimen was not conducted. On the other hand, Tateishi(1985) proposed that Vigna nakashimae should be treated as a subspecies in Vigna minima , under the name Vigna minima (Roxb.) Ohwi & Ohashi subsp.nakashimae (Ohwi)Tateishi.
V.nakashimae and V.minima are grouped in the same subgroup based on the RAPD analysis (Tomooka et al. 1995). 2n=22.
Distribution
Western part of Kyushu (Japan), Korea, Central and North China (Tateishi, 1985).
Characteristics
According to Tateishi(1985), the morphological characteristics of V.nakashimae is as follows. Leaflets lanceolate, ovate, or triangular-ovate, sometimes faintly 3-lobed, acute at the apex, 1-8.5cm long, 0.8-4cm wide. Bracteoles lanceolate or narrowly ovate, 2-3.5mm long, as long as or shorter than caryx.
Flowers pale yellow, smaller than typical V.minima. Ovary 7-8 ovuled. Germination hypocotyl. Primary leaf cordate with petiole.
As genetic resources
The evaluation as a genetic resources, such as resistance against diseases and insects has not been carried out. Therfore, collection and evaluation of this species is considered to be very important.
References
Tateishi,Y. 1985. A revision of the Azuki bean group, the subgenus Ceratotropis of the genus Vigna (Leguminosae). Ph.D. Thesis, Tohoku University, Sendai, Japan.
Tomooka,N., V.A.Sumanasinghe, A.Kaga and Y.Egawa. 1995. Molecular taxonomic relationship among azuki group species in the genus Vigna based on RAPD analysis. Breeding Science Vol.45 (Extra issue 1):181. (in Japanese)