Description

［Objectives］

   Fusarium head blight (FHB) is one of the most destructive diseases that afflict wheat. Repeated screening of genetic resources has led to the identification of several resistant cultivars of spring wheat, such as Frontana from Brazil, Sumai 3 from China and Nobeokabouzu-komugi from Japan. It is known, however, that several morphological and ecological variations with different responses to FHB exist within global accessions of Frontana and Sumai 3, and differing sources of Sumai 3 have been identified by DNA markers. In this study, we revealed genetic variation within accessions of Frontana (Brazil, the United States, Canada and Japan) and Sumai 3 (China, the United States, Canada, Iran, Austria and Japan) that had been sent to the International Maize and Wheat Improvement Center (CIMMYT) by using 242 SSR markers (Fig. 1) which encompass the entire wheat genome.

[Results]

   Frontana-USA and -CAN were found to be identical with, or to be variants of, the original Brazilian accession. In the case of Sumai 3, the American, Canadian and Iranian accessions were of the same genotype as the Chinese accession. Sumai 3-JIR may possibly be a derivative of these accessions. The Austrian accession was determined to be a derivative of an original Chinese accession following out-crossing and selection with additional resistance genes to FHB (Table 1). The results of genetic variation analysis within accessions of Frontana and Sumai 3 reveal that we must always consider the source and genotype of such accessions when evaluating the results of QTL analysis and utilizing them in breeding programs with marker-assisted selection.

Figure, table

1.  

   

   Fig. 1. Morphological variations within Sumai 3 accessions.
   Anthocyanin pigmentation of coleoptiles(A-left) and anthers (B) vs. yellow ones (A-right and C).

2. Table 1. Number of SSR markers showing polymorphism within Frontana and Sumai 3 accessions compared to the Brazilian cv. Frontana-BRZ and the Chinese cv. Sumai 3-CHN.