In the State of Espírito Santo (Brazil), family farmers have grown a number of maize varieties for decades, consisting of open-pollinated populations with valuable importance for the livelihood of smallholder farmers. The study aimed to analyze the cause and effect of associations between agro-morphological traits for increasing yields in maize populations cultivated. A total of 16 maize accessions of in vivo conservation works in eight different locations were evaluated, in a randomized complete block design with three replicates, totaling 48 experimental units. Genetic parameters, genotypic, phenotypic, and environmental correlation were estimated, and a path analysis was conducted. In general, accessions presented enough genetic variability, showing significant differences for all traits analyzed statistically (P≤0.05). The first cob insertion height with plant height and final plant stand variables presented heritability (h2) higher than 80%, suggesting that superior genotypes could be determined. Highest estimates of phenotypic correlations (rp) were found between the first cob insertion height with plant height and total number of cobs with number of cobs per plant (0.85). For estimates of genotypic correlations (rg), the highest were between (i) the first cob insertion height and plant height; (ii) number of grains per row and number of cobs per plant; (iii) total number of cobs and final plant stand. Maize final plant stand and one thousand seed weight were observed to be traits that could be determinant in grain yield increase.