Diallel analysis of Fusarium head blight resistance in genetically diverse winter wheat germplasm

Abstract

New sources of partial resistance to Fusarium head blight (FHB) in wheat have been identified over the past decade; however, little is known of their breeding value. A 20 parent partial diallel that included resistant genotypes from the U.S., Europe, China and South America was used to evaluate the potential of these sources of resistance as parents in wheat breeding programs. Eight plants replication -1 of each of 190 crosses and 20 parents were point-inoculated with Fusarium graminearum under greenhouse conditions in two replicated experiments. Both general (GCA) and specific combining ability (SCA) were significant. Most of the variance for FHB severity was associated with additive genes; however, estimates for SCA ranged from highly negative to highly positive in both resistant 9 resistant and resistant 9 susceptible crosses which suggest that improving FHB resistance through gene pyramiding strategies based on additive genetic variation may be complicated by interaction effects that condition FHB resistance.

Fusarium Head Blight and Rust Diseases in Soft Red Winter Wheat in the Southeast United States: State of the Art, Challenges and Future Perspective for Breeding

“…Plant breeders can have hundreds of thousands of breeding lines per season and are limited in the greenhouse for FHB and rust screening due to time and space constraints. High G×E can result in a poor correlation between greenhouse and field screening for quantitative traits such as FHB severity, DON levels, and FDK which suggests that greenhouse test alone would not be sufficient to explore resistance sources which might actually be expressed only in the field (Hall and Van Sanford, 2003). Regardless of the time and effort, phenotypic screening in multiple environments is still indispensable to lay the foundation for successful MAS and GS.…”