Half-diallel Analysis of Fusarium Head Blight Resistance in Bread Wheat (Triticum aestivum L.)

TO CHARACTERIZE FHB resistance, a set of 48 advanced inbred lines (AILs) along with two Egyptian cultivars (Sakha-93 and Giza-168) were evaluated for their resistance to the FHB during 2015/2016 and 2016/2017 under both greenhouse and field conditions. We identified some resistant AILs to the FHB including 37, 35 and 22 based on percentages of diseased spikelets under both greenhouse and field conditions and free phenolic compounds along with grain yield (GY) under the field condition. While most of the AILs were susceptible to the FHB. Three resistant AILs, three susceptible AILs and an Egyptian susceptible cultivar were crossed in a half-diallel mating system. The parents and the non-reciprocal F1 crosses were evaluated for their response to the FHB under infected conditions in both greenhouse and field conditions. Both general combining ability (GCA) and specific combining ability (SCA) were significant for all studied traits. Both additive and non-additive describes for resistance to the FHB; however, different calculations supported that additive gene action is the preponderant constituent. The moderately high estimates of narrow-sense heritability values implied that further improvement of the FHB resistance could be accomplished through selection. We found that AILs 22, 35 and 37 were good combiners and successfully conveyed their resistant genes to their offspring based on the SCA. These resistant AILs could be integrated in wheat breeding programs using bi-parental or multi-parental populations to develop new resistant varieties to FHB. In addition, they can be exploited to improve existing cultivars using backcrossing approach.