INHERITANCE OF GRAIN YIELD AND ITS COMPONENTS IN THREE BREAD WHEAT CROSSES (TRITICUM AESTIVUM L.)

ABSTRACT
Bread wheat (Triticum aestivum L.) is a major staple in Egypt, yet domestic production remains insufficient to meet growing demand. This study was carried out to evaluated the genetic control of grain yield , its components, heritability, and genetic gains across segregating generations. Five diverse wheat cultivars (Sids 14, Misr 3, Sakha 93, Gemmeiza 12, and Giza 171) were used to develop three hybrid combinations (Sids 14 × Sakha 93, Misr 3 × Giza 171, Gemmeiza 12 × Giza 171). Experiments were conducted over four consecutive seasons (2019/2020–2022/2023) using a randomized complete block design with three replications. Evaluated traits included spikes/plant, kernels/spike, 100-kernel weight, and grain yield/plant. Significant variability was observed among parental and segregating populations. Positive heterosis was recorded for most traits, especially spikes/plant and kernels/spike, while inbreeding depression in F₂ populations indicated partial loss of hybrid vigor. Genetic analysis revealed substantial contributions of both additive and dominance effects, with epistatic interactions affecting key yield traits. Broad-sense heritability was high for kernels/spike and grain yield, whereas narrow-sense heritability varied across traits. Expected and realized genetic gains were highest for grain yield and kernels/spike, confirming the effectiveness of selection. These results suggest that targeted breeding focusing on traits with high heritability and favorable additive effects, while considering non-additive interactions, can enhance wheat productivity. The findings provide guidance for developing high-yielding cultivars to help close the production-consumption gap in Egypt.