Gamma irradiation of eggplant seeds influences plant growth, yield and nutritional profile in M1 generation

The study examines agromorphological traits and nutrient compositions in three genotypes of eggplants (Solanum melongena ‘African Beauty F1’ and ‘Melina F1’ and S. aethiopicum ‘Kotobi’) grown from seeds irradiated by gamma rays (γ-ray) with 100 Gy. Experiments were carried out in the screenhouse and experimental field of Crop Science Department, University of Calabar, Nigeria. Completely randomised design with four replications and randomised complete block design with three replications was used in the screenhouse and field experiments respectively. Eggplant × γ-ray effect reduced (p ≤ 0.05) seedling emergence, plant height and number of leaves in the nursery at 2 and 4 weeks after sowing. In the field, these traits were consistently lower for irradiated Melina F1 and Kotobi (p > 0.05) at ten weeks after transplanting. Irradiated African Beauty F1 had the highest (p ≤ 0.05) upper canopy leaf area (429.54 cm2), higher (p > 0.05) plant height and stem width; lower (p > 0.05) number of branches and leaves. Un-irradiated and irradiated Kotobi had the highest (p ≤ 0.05) fruit load, lower (p ≤ 0.05) fruit volume, weight and yields over four harvest intervals. Carbohydrate and energy contents of Kotobi fruits grown from 100 Gy gamma-ray irradiated seeds were concurrently improved (p ≤ 0.05). Gamma ray irradiation had both positive and negative influences on the agromorphological traits, mineral composition and nutrient profile of eggplants. However, 100 Gy dose of irradiation had a negative effect on fruit characteristics in general. From the results of this study, inconsistent variations in the agromorphological traits of the irradiated eggplants of the three varieties were reported. Therefore, the goal of mutation breeding in eggplant should not undermine the importance of the eggplant genotype as well as the actual radiation dose.