Combining ability analysis and estimation of heterosis for resistance to head blight caused by Fusarium graminearum in spring wheat

Fusarium graminearum Schwabe, the causative agent of Fusarium head blight (FHB), is an economically important pathogen of wheat. Improvement of the FHB resistance by developing new varieties requires sound knowledge on the inheritance of resistance. A half diallel cross using seven spring wheat genotypes was carried out to estimate inheritance for disease index (DI), disease incidence (DIC), disease severity (DSV), Fusarium damage kernels (FDK) and incidence-severity-kernels (ISK). Analysis of variance for studied traits indicated highly significant differences among the genotypes. In all traits, significant general combining ability (GCA) revealed meaningful contributions of additive type of gene action in governing the traits. Specific combining ability (SCA) effects were significant only in DIC and FDK. Ratio of GCA to SCA indicated the preponderance of additive gene effects in determining the inheritance of all traits. High broad sense heritability was measured for all characters, allowing for considerable progress by selection.