Estimation of Some Genetic Parameters and Stability of Growth and Quality Traits for Six Soybean (Glycine max L. Merr) Cultivars under Nano-Phosphate Fertilizer Levels

Abstract

Background: Soybean productivity and seed quality are strongly influenced by genetic makeup and nutrient management. This study aimed to estimate genetic parameters and stability of six soybean (Glycine max L. Merr) cultivars and to evaluate their response to different levels of nano-phosphate fertilizer under field conditions. Methods: A field experiment was conducted during the summer season of 2024 in northern Kirkuk Governorate. Six cultivars (Iman, Energy-2, Energy-3, Lee-74, Shaima, and Senaia-2) were evaluated under six nano-phosphate levels (0, 1000, 2000, 3000, 4000, and 5000 mg/kg). The experiment was arranged in a split-plot within a Randomized Complete Block Design (RCBD) with three replications. Genetic parameters including genotypic (σ2G), environmental (σ2E), and phenotypic (σ2P) variances, broad-sense heritability (h2bs), stability analysis, and genetic correlation coefficients were estimated. Results: Oil yield showed positive and highly significant genetic correlations with number of vegetative branches (0.938**), effective branches (0.528**), protein content (0.822**), protein yield (0.998**), and oil content (0.842**). Broad-sense heritability was high for most traits, reaching 70.04% for protein yield and 69.95% for oil yield, indicating predominance of genetic effects and effectiveness of selection. The highest genotypic and phenotypic variances were observed for number of leaves and effective branches. The cultivar Lee-74 (G4) recorded the highest protein and oil yields and was identified as the most genetically stable and high-performing cultivar. Highest protein yield, and oil yield, were for Lee-74 (G4) cultivar which was identified as the genetically stable cultivar with high yield, representing the ideal cultivar for cultivation.