Screening for Resistance to Artificial Infection by Common Bunt (Tilletia caries and Tilletia Foetida) in F2 Populations of Wheat (Triticum Aestivum L.)

Abstract

The species of Tilletia which cause common bunt of wheat (Tilletia caries and Tilletia foetida) can cause major yield losses in common wheat (Triticum aestivum L.) and durum wheat (Triticum turgidum L.). The aim of this study was to test resistance to Tilletia spp. of eight F2 populations of wheat consisting of progenies derived from resistant x susceptible crosses. Tests were carried out in the field by artificial inoculation of wheat seeds with a mixture of spores of T. caries and T. foetida. Analysis of variance for the percentage of infected plants showed that there were statistically significant differences between tested F2 progenies (between the progenies derived from crosses) regarding percentage of infection with Tilletia spp. (varying between 18.4 and 63%). The progenies of four crosses were tested comparatively using two different doses of inoculum, in order to find out the infection degree. Significant differences were observed between the bunt incidence after inoculation with the two doses. Characterization of the resistance in F2 progenies allowed us to perform a genetic analysis on the inheritance of resistance to Tilletia spp. in F2 population. The chi-square (χ2) analysis showed that inheritance of resistance to Tilletia spp. in progenies of F2 segregating populations fit a 3:1 (resistant:susceptible) ratio for the segregation of a single major resistance gene. The exception is represented by the segregation of resistance in F2 progenies of five crosses that do not fit the expected ratio of 3:1, which is possible because of the small number of plants that could be evaluated in tested population.