普通小麦籽粒DON含量的配合力分析

为了选育抗赤霉病且籽粒毒素含量低的小麦品种以减轻赤霉病危害，在对我国南方麦区地方品种进行赤霉病抗性鉴定的基础上，选用8个籽粒中脱氧雪腐镰刀菌烯醇（deoxynivalenol, DON）含量水平不同的小麦品种作亲本，按8×8半双列杂交配制28个杂交组合，以接种后成熟籽粒中DON含量、病小穗数、病小穗率和病粒率为指标，进行赤霉病抗性、一般配合力（GCA）和特殊配合力（SCA）遗传分析，以及不同鉴定指标间比较和相关性分析。结果表明，8个品种中籽粒DON含量以苏麦3号最低(0.5715 mg kg^-1)，Alondra’s最高(13.5560 mg kg^-1)，各组合F1的籽粒DON含量均低于感病品种Alondra’s。品种间GCA和SCA存在显著差异，籽粒DON含量以加性效应为主，存在部分显性效应。苏麦3号、望水白和翻山小麦表现出较好的一般配合力效应。以苏麦3号为亲本的5个组合、望水白为亲本的4个组合特殊配合力效应较大。扬麦158一般配合力效应较小，但有4个组合表现较好的特殊配合力效应。籽粒DON含量和病小穗数、病小穗率、病粒率呈极显著的正相关关系。感病品种Alondra’s和绵阳8545的各个抗性鉴定指标的一般配合力在8个品种的排序中表现一致，抗病品种各个抗性指标的一般配合力在8个参试材料间的排序有所差异。DON含量的狭义遗传力为74.54%，因此以抗DON积累为指标的赤霉病抗性育种，可以在早期世代进行选择。

Analyses of Combining Ability of DON Content in Wheat Grains

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.