Genetic Parameters and Stability of Soybean [Glycine max (L.) Merr.] Cultivars under Nano-phosphorus Foliar Fertilization Levels

Soybean is considered one of the most important economic crops; however, its productivity is influenced by genetic variability among cultivars and their response to phosphorus fertilization levels. The use of nano-phosphorus fertilizer contributes to enhancing growth efficiency and yield, which necessitates genetic evaluation of soybean cultivars under such fertilization conditions.

A field experiment was conducted in northern Kirkuk during the summer season of 2024 to estimate genetic parameters and analyze genetic relationships among six soybean cultivars (Iman, Taqa-2, Taqa-3, Lee-74, Shaima, Senaia-2) under six levels of nano-phosphorus foliar fertilizer (0, 1000, 2000, 3000, 4000 and 5000 ppm). The experiment was laid out in a randomized complete block design (RCBD) with a split-plot arrangement and three replications. Sowing was carried out on May 20, 2024.

The data showed high estimates of genetic variance (σ²G), environmental variances (σ²E) and phenotypic variances (σ²P), while broad-sense heritabilities reached a high of 91.65%. There were significant positive genetic correlations between seed yield and number of pods per plant (0.731**), number of seeds per pod (0.819**) and 1000 seed weight (0.956**). The variances and coefficients of variation for total seed yield per plant were 41073.86, 3740.47, 44814.33 and 8.70% and 8.33%, respectively. GGE Biplot analysis revealed that the genotype Lee-74 was the most stable and superior line for seed yield per plant. The results from hierarchical cluster analysis revealed that the pair of Iman and Shaima was the closest in genetic relationship (248.27) and the most distant between Taqa-2 and Lee-74 (68233.67).