Determination of Inheritance of Spike Traits Through Five Parameter Model in Segregating Populations of Wheat

The present study was carried out to assess the inheritance of bread wheat for spike related traits by developing five generations (P₁, P₂, F₁, F₂, and F₃) from seven bread wheat cross combinations. The multi-location testing and five parameter model was applied to get a clear insight into gene effects controlling the traits. All generations of each cross were sown at two locations. Analysis of variance (ANOVA) revealed significant effect of environment on all the traits. Significant to highly significant differences were observed among generations (P₁, P₂, F₁, F₂, and F₃) in most of the cross combinations. Significant generation × location interaction was also noted in most crosses. The data on generation means indicated that the Maxipak variety and its segregating generations exhibited the highest mean values for spikelets per spike (22.7) and awn length (8.6 cm). The highest mean for spike length was recorded in the F₁, F₂, and F₃ generations of RK-23 × Gold. Gene action studies revealed that the inheritance of spike length and spikelets per spike was predominantly controlled by additive and epistatic gene effects in most cross combinations. Awn length was mainly influenced by dominance × dominance gene effects in most crosses, although some cross combinations also exhibited dominant and additive types of gene action. Therefore early generation selection is effective for spike length and spikelets per spike, while selection should be conducted in later generations for awn length.