Genetic characterization of white onion genotypes (Allium cepa L.) using ISSR markers

Understanding the genetic characteristics is crucial for preserving and developing Moroccan's white onion genotypes, with increased yield and quality as well as improved tolerance to biotic and abiotic stresses. In the present paper, inter simple sequence repeat (ISSR) markers were used to assess the genetic diversity and characteristics of white onion genotypes (Allium cepa L.) of Morocco. Based on the ISSR markers bands, 28 white onion genotypes were divided into four distinguished subgroups, with a genetic similarity value of 0.46 based on Jaccard index. Molecular markers analysis revealed that all ISSR markers were 100 % polymorphic with the white onions genotypes. Concerning markers performance, polymorphic information content (PIC) ranges from 0.051 to 0.39 with a mean of 0.301; however, the effective multiplex ratio (EMR) and marker index (MI) vary between 3–17 and 0.35–5.04, respectively. Based on resolving power (RP), it appears that the marker UBC825 has an efficient discriminatory power with an RP = 15.67. In contrast, the lowest RP value was detected with the marker UBC815 (RP = 1.58). Based on their high performance, markers UBC825, UBC835, UBC826, UBC840, and UBC811 ISSR seem to be specific and efficient for the identification of Moroccan white onion genotypes. Thus, given the genetic diversity shown by ISSR markers, the abundant resources of white onion genotypes in Morocco could be exploited in more valuable ways.