Homoeology of Thinopyrum junceum and Elymus rectisetus chromosomes to wheat and disease resistance conferred by the Thinopyrum and Elymus chromosomes in wheat.

Thirteen common wheat "Chinese Spring" (CS)-Thinopyrum junceum addition lines and three common wheat "Fukuhokomuji"(Fuku)-Elymus rectisetus addition lines were characterized and verified as disomic additions of a Th. junceum or E. rectisetus chromosome in the wheat backgrounds by fluorescent genomic in situ hybridization. Another Fuku-E. rectisetus addition line, A1048, was found to contain multiple segregating E. rectisetus chromosomes. Seven partial CS-Th. junceum amphiploids were identified to combine 12-16 Th. junceum chromosomes with CS wheat chromosomes. The disomic addition lines AJDAj5, 7, 8, 9, and HD3508 were identified to contain a Th. junceum chromosome in homoeologous group 1. Two of them, AJDAj7 and AJDAj9, had the same Th. junceum chromosome. AJDAj2, 3, and 4 contained a Th. junceum chromosome in group 2, HD3505 in group 4, AJDAj6 and AJDAj11 in group 5, and AJDAj1 probably in group 6. The disomic addition lines A1026 and A1057 were identified to carry an E. rectisetus chromosome in group 1 and A1034 in group 5. E. rectisetus chromosomes in groups 1-6 were detected in A1048. The homoeologous group of the Th. junceum chromosome in HD3515 could not be determined in this study. Several Th. junceum and E. rectisetus chromosomes in the addition lines were found to contain genes for resistance to Fusarium head blight, tan spot, Stagonospora nodorum blotch, and stem rust (Ug99 races). Understanding of the homoeology of the Th. junceum and E. rectisetus chromosomes with wheat will facilitate utilization of the favorable genes on these alien chromosomes in wheat improvement.