Morphology of Chinese Chive and Onion (Allium; Amaryllidaceae) Crop Wild Relatives: Taxonomical Relations and Implications

The genus Allium L. includes economically significant crops such as Chinese chives (Allium tuberosum Rottler ex Spreng.) and onions (Allium cepa L.), and is utilized in diverse agricultural applications, with numerous cultivars developed to date. However, these cultivars are facing a reduction in genetic diversity, raising concerns regarding their long-term sustainability. Crop wild relatives (CWRs), which possess a wide range of genetic traits, have recently gained attention as important genetic resources and priorities for conservation. In this study, the taxonomy of Allium species distributed in Korea is assessed using morphological characteristics. Two types of morphological analyses were conducted: macro-morphological traits were examined using stereomicroscopy and multi-spectral image analyses, while micro-morphological traits were analyzed using scanning electron microscopy. We detected significant interspecific and intraspecific variation in macro-morphological traits. Among the micro-morphological features, the seed outline on the x-axis and structural patterns of the testa and periclinal walls were identified as reliable diagnostic characters for subgenus classification. Moreover, micro-morphological evidence contributed to inferences about evolutionary trends within the genus Allium. Based on phylogenetic relationships between wild and cultivated taxa, we propose an updated framework for the CWR inventory of Allium.