Abstract:

Fusarium head blight (FHB) caused by Fusarium spp. is an important disease of wheat in warm and humid areas in the world. In China, frequent epidemics of wheat FHB occurred mainly in the middle and lower reaches of the Yangtze River and the northeastern spring wheat growing area. FHB causes decrease of grain yield and quality. Moreover mycotoxins contamination of diseased wheat grains is harmful to humans and livestock. Deoxynivalenol (DON) is the main toxin in wheat in China. Many countries had regulations for DON contents in both food and feed. Development of scab-resistant cultivars with minimizing DON content can reduce the damage from FHB. In the present research, to understand the inheritance of DON content in wheat grains, an 8×8 diallel crossing of GriffingⅡ analysis of DON content involving four landraces (Wangshuibai, Chimianxiaomai, Fanshanxiaomai, and Qiangweimai) and four cultivars (Alondra’s, Mianyang 8545, Sumai 3, and Yangmai 158) with different DON content was performed. F1 of 28 combinations and their parental lines were planted with two replications and artificially inoculated by single floret inoculation with a high DON-producing isolate. Disease severity was evaluated by the number of diseased spikelets, percentages of diseased spikelets and diseased grains, and DON content in grains was analyzed by gas chromatography with mass spectrometry (GC/MS). The above four indices were compared and their correlation coefficients were estimated. General combining ability (GCA) and special combining ability (SCA) were also analyzed. Significant differences of DON content, GCA and SCA of DON content in wheat grains were measured among the eight parents. All F1 hybrids showed less DON contents than the susceptible cultivar Alondra’s. The resistant cultivar Sumai 3 showed the lowest DON content (0.5715 mg kg^-1) and the highest negative GCA values (－1.26), and Alondra’s showed the highest grain DON content (13.5560 mg kg^-1) and highest positive GCA values (2.96). Negative GCA effects of Sumai 3 (－1.26), Wangshuibai (－1.16) and Fanshanxiaomai (－1.13) were similar and significant for decreasing DON content. Five combinations derived from Sumai 3, four from Wangshuibai and four from Yangmai 158 showed higher SCA for DON content reduction. From the results of the current research, the DON content in grains is mainly controlled by additive genetic components, with partial dominance effects. There were significant positive correlations among DON content, number of the diseased spikelets, percentages of diseased spikelets and diseased grains (r = 0.5980－0.9889). In addition, GCA of four parameters in susceptible cultivars（Alondra’s, Mianyang 8545）showed the same trend in the eight parents, while it varied among different resistant cultivars. The narrow sense heritability of DON content in grains was 74.54%, indicating that it is feasible to select lines with low DON content in earlier generations.

Key words: Triticum aestivum, Fusarium head blight (FHB), Combining ability, Deoxynivalenol (DON), Heritability