Genetic Analysis of Grain Yield and Its Components in Bread Wheat (Triticum aestivum L.)

Aims: Increasing yield is the most important aim in any breeding program. Since yield is a complex trait with low inheritance and involves several quantitative components, its direct study is not usually sufficient and therefore it is suggested that its components be investigated instead. Awareness of gene action of traits is very important in plant breeding methods.
Study Design: The experiment was conducted using a randomized complete block design with two replications for each generation.
Place and Duration of Study: P1, P2, F2, F3 and F4 generations of a Gaspard (sensitive) × Kharchia (tolerant) cross were used as genetic materials. The parents and F2, F3 and F4 populations were grown in 2010-2011 growing season in the research farm of international center for sciences, High Technology & Environmental Science-Kerman Iran.
Methodology: Generation mean analysis using parents (Gaspard & Kharchia) and their progenies (F2, F3, F4) was used to study the type of gene action and the best genetically model of traits under drought stress condition.
Results: Generation mean analysis was performed by scaling test. Meanwhile, the three parameter model the additive-dominance was adequate to demonstrate the genetic variation and it is important in the inheritance of spike length with awn, flag leaf length and flag leaf width. Generation means analysis revealed all types of gene action (additive, dominance and epistatic) were involved in the inheritance of grain yield, plant height, spike length and total spike weight of plant. In inheritance the peduncle length, number of grain per plant were effective additive effect and additive × additive epistatic effect. Dominance effects were more important than additive effects in most traits.
Conclusion: Therefore to improve these traits hybridization and using of hybrid vigor would be much efficient than the selection strategies.