Components of Genetic Variance and Combining Ability Analysis in Wheat (Triticum aestivum L.)

Background: Wheat is a major cereal crop, ranking first in global production. The Line x Tester analysis identifies the best-performing combinations based on the general combining ability of parents and specific combining ability of hybrids. This information helps in selecting suitable parents for developing high-yielding hybrids. Methods: The experiment involved forty-five genotypes, including thirteen parental lines (ten lines and three testers), thirty F1s and two checks, to estimate variance components and combining ability using a Line x Tester mating design in wheat (Triticum aestivum). It was conducted in a randomized block design (RBD) during the Rabi seasons of 2021-2022 and 2022-2023 at the Agriculture Research Farm, Department of plant breeding and genetics, Lovely Professional University, Phagwara (Punjab). Result: The results showed significant genetic variability among lines, testers and hybrids. The variance due to specific combining ability (σ2s) was higher than that due to general combining ability (σ2g). Dominance genetic variance (σ2D) was greater than additive genetic variance (σ2A) and the degree of dominance was greater than one ( greater than 1) for most traits, except for plant height and flag leaf area in F1s. The predictability ratio was less than one ( less than 1) for all traits, indicating the presence of non-additive gene action with some influence of additive gene. General combining ability (GCA) analysis identified lines such as PBW677, 10th HPYT438 and 10th HPYT422, along with tester HD3226, as good combiners with strong potential for developing improved wheat lines through hybridization. Specific combining ability (SCA) analysis showed PBW677 x PBW725, 10th HPYT422 x HD3226, PBW677 x DBW222 and 10th HPYT402 x DBW222 as the best specific combiners, suggesting their potential for yield enhancement in breeding programs. These findings are an important step in advancing wheat breeding programs and ensuring sustainable food production.