Enhancing and comparison of yield components through diallel analysis in F1, F2, F3 and F4 barley (Hordeum vulgare L.) populations

Developing high-yielding cultivars requires understanding genetic variation in yield and its components. The study aimed to investigate the genetic structure and inheritance of key traits to identify suitable parents and promising hybrid combinations across F1–F4 generations, using a randomized complete block design with three replications (2019–2023). Data analysis included Griffing Method I, Model 1, general combining ability (GCA) and specific combining ability (SCA) analysis, full diallel variance analysis, Jinks-Hayman diallel hybrid analysis, and heterosis-heterobeltiosis ratios. The Arcanda cultivar showed strong general combining ability, while the Arcanda/Asparuh and Alena/Asparuh hybrid combinations exhibited significant specific combining ability. In the F1–F4 evaluations, Arcanda × Asparuh achieved the highest yields (30.43 g plant−1; 340.40 g 1 m⁻1; 8500.0 and 9151.0 kg ha⁻1), with mean heterosis and heterobeltiosis values of 37.32% and 23.07%, respectively. Alena × Asparuh also performed strongly, particularly in F3 (8459.0 kg ha⁻1), and exhibited high heterosis in F1. High heterosis and heterobeltiosis values, especially for grain yield and thousand kernel weight indicate substantial potential for genetic improvement. To assess the kinship of the parental lines, iPBS-retrotransposon primers were used. The Alena and Arcanda cultivars showed 78% similarity, while the Asparuh cultivar showed 71% similarity to the other parents. In conclusion, Arcanda × Asparuh and Alena × Asparuh consistently combined high yield with genetic stability, making them strong candidates for breeding high-performing barley cultivars. Delaying selection to the later F3–F4 generations increases the accuracy of identifying and stabilizing superior hybrids, thereby maximizing genetic potential and enhancing agricultural productivity.