The experiment commenced in the shade house at Al-Mahaweel Horticulture Station, located in the north of Babylon Province, Iraq, from April to November 2021. It studied the effect of bio fertilizers and nanofertilizers on traits of some root and vegetative growth of orange (Citrus sinensis L. Osbeck). The experiment had a factorial setup (4 × 4) with a completely randomized design and three replicates. The two factors included nanofertilizer with four levels at 0, 1, 2, and 3 g L^-1 and corresponding symbols (N0, N1, N2, and N3, respectively). The second factor was the bio fertilizers with four levels (control and azotobacter at 10 ml L^-1 pot, mycorrhiza at an average of 10 gm pot^-1, and a mixture of mycorrhiza and azotobacter as ground additive), symbolized as F0, F1, F2, and F3, respectively. The results showed the treatment of F3 excelled, giving the highest rate for the traits of the number of leaves, plant height, leaf area, root length, and the number of roots. Their corresponding values reached 125.93 leaves plant^-1, 72.30 cm, 83.17 cm², 121.52 cm, and 7.89 roots plant^-1, respectively. The treatment of N3 stood out, and it gave the highest rate for the traits of leaf number, plant height, leaf area, root length, and numbers, with values at 66.15 leaves plant^-1, 139.01 cm, 94.64 cm², 138.38 cm, and 9.195 roots plant^-1), respectively. Meanwhile, the bi-interaction treatment (F3 + N3) was superior, providing the maximum values for all studied traits.

Keywords: Orange (Citrus sinensis L.), bio fertilizers, nanofertilizers, growth traits

Key findings: The treatment of F3 was excellent, and it gave the highest rate for the traits of the number of leaves, plant height, leaf area, root length, and the number of roots.