Inheritance of Resistance to Brown Rust Disease in Bread Wheat Via Means of Generation Analysis

Brown wheat rust caused by Puccinia recondita f. sp tritici is one of the most important diseases of wheat in most parts of regions in the world. The progeny of F1, F2, BC1 and BC2 derived from cross of Bolani×ATRI525 and Bolani×ATRI527 with parents, were cultured in a completely randomized block desigen for the study of wheat rust resistance. Trait such as infection, Infection type, contamination coefficient and surface under the disease progression curve were measured and evaluated. Genetic analysis by analysis of means and variance of generations showed that in addition to increasing effects, epistatic effects also play an important role in the control of traits. However, dominance variance had an important role in the control of traits in the incremental variance and there was a significant difference between the generations in terms of all traits in the one percent (P<0.01) level. The results of genotyping average analysis indicated that the dominance of genes was the most important genetic factor in control of the studied traits. Epistatic additive×additive incremental addiction was more important than the epistatic dominance×dominance. The average of heritability for the traits was the percentage of infection, type of contamination, contamination coefficient and under curve of disease progression were 0.88, 0.92, 0.82 and 0.86 for the first population and 0.75, 0.68, 0.62 and 0 59 for the second population. Private heritability for the above mentioned traits was varied by 0.42, 0.34, 0.52 and 0.17 for the first population, and 0.45, 0.39, 0.46 and 0.19 for the second population. The mean genetic dominance (√(H/D) was less than one for all four attributes, indicating the role of dominance effects in trait control.