Phenotypic diversity for morphological and agronomic traits in traditional Ethiopian highland maize accessions

Farmers in the highlands of Ethiopia have developed locally adapted maize varieties for more than 300 years. In order to assess the phenotypic diversity among traditional Ethiopian highland maize accessions, a total of 180 accessions were evaluated for agro-morphological traits in a replicated randomized complete block design. The accessions varied significantly for all of the measured traits. Cluster analysis revealed the presence of four major clusters. Accessions collected from the different regions were distributed over all the phenotypic clusters, reflecting wide variation within a particular region, but low differentiation among regions. The first principal component, which explained 40.4% of the total variation, was due to days to tasseling and silking, plant and ear height, leaf length and days to maturity. Traits directly selected by farmers (yield, kernels per row, rows per ear, and ear height) had the highest phenotypic coefficient of variation (PCV), whereas indirectly selected traits (ear diameter, days to tasseling and silking) showed lower PCV values. Number of kernels per row had high heritability and genetic advance as percent of the mean and could be used as selection criterion to increase grain yield. Overall, the study indicated the existence of ample trait diversity in highland maize accessions, which can be exploited by hybridization and selection.