Interest in growing lentil (Lens culinaris Medik.) is increasing due to its potential returns relative to other legume crops in semi-arid areas. An experiment was conducted to examine the important traits on lentil under application of nano-fertilizer by using eight genotypes with application of the biplot technique in visualizing research data. Nano-iron oxide (2 g L-1) was utilized as foliar spray during vegetative and reproductive stages. The study revealed that genotype by trait (GT) biplot can graphically display the interrelationships among traits and facilitate visual comparison of genotypes. The first two principal components (PC1 and PC2) accounted for 76% of the total variation. The polygon view of GT biplot suggested four sections for the lentil genotypes as well as traits. The vertex genotypes G1 had plant height, number of branches per plant, number of pods per plant, 100-grains weight and grain yield traits. The most prominent relation were: a strong positive association among biological yield, number of branches per plant, number of pods per plant, grains yield and plant height as indicated by the small obtuse angles between their vectors. The traits’ relationship in the semi-arid was highly variable, and grain yield improvement can be achieved by selecting for number of pods per plant, 100-grains weight. We suggest that the GT biplot be used jointly to better understand and more fully explore interaction pattern data.