Analysis of genetic diversity and population structure in Saharan maize (Zea mays L.) populations using phenotypic traits and SSR markers

Algerian maize has been cultivated in Saharan Oases for many centuries, determining its adaption to extreme environments. Therefore, maize landraces from Sahara could be considered as valuable genetic resources for breeding. Morphological and molecular characterization of fifty-six populations were assessed using 14 agro-morphological traits and 18 SSR markers. Populations were evaluated in field experiment in an augmented randomized complete block design. ANOVA on morphological data revealed significant difference among populations. Analysis of principal component showed two principal components describing 55.44% of total variation. Flowering time, plant height, ears traits and yield were the most discriminatory traits. Genetic analysis identified a large number of alleles (191) with mean value of 10.61 alleles per locus. High average PIC value (0.57) indicates informativeness of the selected markers in this study. The genetic structure analysis revealed a high genetic differentiation (Fst=0.22) among populations, showing a greater genetic diversity within Algerian populations than among them. Bayesian model-based structure analysis assigned genotypes into two groups. Both phenotypic and SSR analysis revealed significant genetic diversity; albeit a clustering based on geographic origin was not observed. The wide genetic diversity of Saharan maize populations could be used as genetic resources in future maize breeding programs.