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

The genus <i>Allium</i> L. includes economically significant crops such as Chinese chives (<i>Allium tuberosum</i> Rottler ex Spreng.) and onions (<i>Allium cepa</i> 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 <i>Allium</i> 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 <i>x</i>-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 <i>Allium</i>. Based on phylogenetic relationships between wild and cultivated taxa, we propose an updated framework for the CWR inventory of <i>Allium</i>.