Analysis of Qualitative and Quantitative Traits to Identify Different Chinese Jujube Cultivars

Chinese jujube (Ziziphus jujuba Mill.) is highly resistant to environmental stress and can be easily cultivated, thus many jujube cultivars are being developed. However, the same cultivars had been cultivated with different names. Thus, systematic management is required to protect the intellectual property of different varieties. To aid systematic control of jujube cultivars, this study presents efficient markers for distinguishing cultivars through identification of morphological characteristics and relationships among 25 jujubes. Among 10 qualitative characteristics, flowering time, fructification time, presence of thorns, and shape of fruit were found to be useful traits for the cultivar identification. In the results of principal component analysis, 3 principal components (PC) represented 73% for the total variations. PC1 showed high positive correlations with fruit–related characteristics and PC2 formed a cluster with leaf-related characteristics. Therefore, the differences in fruit and leaf were identified as useful traits for the cultivar identification. According to the results of cluster analysis, which largely divided cultivars into 4 clusters, Sour jujube 2, with smaller fruits and leaves, was separated first. Cluster II included Chinese cultivars with large fruit sizes, such as Dalizao, Dabailing, Damaya, and Daguazao. Three Korean cultivars were grouped with Bokjo, Panzao, Zanhuangdazao, and Jinsi No. 3, and the remaining 13 cultivars formed a separate cluster.