Hybrid Vigor And Combining Ability Of Faba Bean Genotypes And Their Crossbreeds As Affected By Arginine Spraying

Abstract

This study was conducted during the 2022/2023 and 2023/2024 agricultural seasons at the Zafaraniya Research Station of the Horticulture Department. The aim was to evaluate the genetic diversity of 13 broad bean cultivars and assess the performance of their individual hybrids under the influence of arginine spraying at two concentrations (0 and 250 mg/L⁻¹). The first season included molecular analysis using SSR and RAPD techniques. Based on these results, six cultivars were selected that showed clear genetic divergence and low tannin and vicine contents. The selected cultivars were introduced into a crossbreeding program to produce 15 first-generation (F₁) hybrids, which were studied with their parents in the second season. The experiment was implemented in a split-plot design within a randomized complete block design with three replicates. Data were statistically analyzed using SAS software and Duncan's multiple range test at the 0.05 probability level. Genetic components were estimated using the Griffing (1956) method (second method) within the fixed model. The results showed significant variation in general and specific combining ability, with parents 4 and 5 showing the best positive general combining ability under the arginine treatment, while parent 6 recorded the lowest general combining ability for most traits. Several hybrids, including 5x4, 6x5, and 2x1, showed significant specific combining ability. Dominant genetic variances exceeded additive genetic variance for most traits under treatments A₀ and A₁, indicating the importance of dominance gene action. Genotypic values also exceeded environmental variance for most traits, indicating the presence of a genetic basis that can be exploited in faba bean genetic improvement programs.