Inheritance of common bunt resistance in androgenetically derived doubled haploid and random inbred populations of wheat

Random inbred lines, derived from random head-to-rows, and doubled haploids, derived androgenetically, represent two types of progeny populations valuable in genetic studies, This study was undertaken to estimate inheritance in wheat (Triticum aestivum L.) of resistance to common bunt [Tilletia tritici (Bjerk.) G Wint. in Rabenh.; syn. Tilletia caries (DC.) Tul. & C. Tul.] in random inbred and doubled haploid populations with common parentage. The bunt susceptible experimental line HY377 was crossed with the bent resistant lines SC8021V2 and L8474D1, The populations formed were DH-HY377/8021 and DH-HY377/8474 (androgenetically derived doubled haploid) and R-HY377/8021 and R-HY377/8474 (random inbred). Trials grown both in the growth chamber and the field were inoculated with common bunt of wheat race T19, The F-1 plants from both crosses expressed resistance intermediate between the parents indicating incomplete dominance of gene expression, Resistance segregating from progenies of the cross L8474D1 by HY377 fit a one and not a two gene expected ratio in both the DH-HY377/8474 and R-HY377/8474 populations. The results indicate the segregation of a single major gene for resistance in L8474D1, Segregation of resistance from SC8021V2 in the R-HY377/8021 population fit the expected ratio for one and not two major genes. Comparison of variances of the resistant progeny class and resistant parent indicate at least one minor gene segregating in addition to the one major gene, The size of the DH-HY377/8021 population was too small to make conclusions about gene segregation. Where population size was not limiting, conclusions regarding modes of inheritance were similar from both doubled haploid and random inbred line populations. Lines tested in the growth chamber could he classified for resistance more readily than lines tested in the field.