Abstract

A field experiment was conducted in the autumn season of (2024) in Diyala Governorate to estimate the genetic parameters and analyze the path coefficient when spraying boron at a concentration of 150 mg/L¹ according to the plant growth stages, which are (the five-leaf stage S:2, the growth point differentiation stage S:3, the priming stage S:5, and the flowering stage S:6). For seven varieties of sorghum, namely (Rabih, Buhuth, Enqaz, Giza, Lilo, G, and Khair), according to the split-plot system with a complete randomized block design and three replicates, the main plots contained the boron spraying stages, while the secondary plots included the varieties. The study showed values of genetic variance and phenotypic variance were higher values of environmental variance in most of the studied traits and at all stages of boron spraying, the coefficients of genetic variation were between medium and low for all stages of boron spraying, while the phenotypic variation coefficients were high for the trait of number of head seeds, head weight and biomass yield in the fourth stage of boron spraying, which were (31.139, 34.887, 33.563) respectively. As for the heritability in the broad sense, it was high for each of the traits of number of head seeds, head diameter, biomass yield, and grain yield, and they reached (70.132, 60.835, 61.665, 61.422) respectively. the expected genetic advance as a percentage, it was high for the trait of number of head seeds and biomass yield (40.529, 35.189) respectively. While the path coefficient analysis showed high direct effects for number of head seeds, head weight, head diameter, 1000-grain weight, biomass yield and harvest index at different stages of boron application, the indirect effects were high for plant height, number of head seeds, head weight, head diameter, 1000-grain weight and biomass yield at different stages of boron application.