2020 Volume 89 Issue 1 Pages 12-21
Brassica napus L. is one of the most important oilseed crops in the world. The flower stalks (lateral shoots) of the leafy vegetable B. napus landrace, commonly known as norabona, are consumed for nutritional purposes and these plants are grown in the Kanto region of Japan. In the present study, we revealed the diversity of norabona at genotypic and phenotypic levels. Samples were collected from four different areas in the Kanto region of Japan and comprised other leaf vegetable landraces (kakina; B. napus and komatsuna; B. rapa). Phenotypic traits were assessed by investigating six morphological traits and five compositions for flower stalks. Principal component analysis in multivariate analysis demonstrated that the 20 norabona and kakina samples in the present study could be separated into three clusters. Genotyping using a total of 24 simple sequence repeat markers and Nei’s matrix genetic distances and neighbor-joining clustering method led to the partitioning of 23 samples into three groups and komatsuna. The genotypic Group 1b comprised the largest number of norabona samples; the farthest geographic distance was observed in genetically close pairs. On the basis of our results, we concluded that (1) the norabona population in Japan is phenotypically diverse and that (2) this population is not genetically identical, but consists of different genotype subpopulations that are geographically not divergent.
