Wheatgrass-wheat hybrids as a novel source of stem rust and Fusarium head blight resistance

Perennial wheatgrass (Thinopyrum) species are recognized as a source of genetic variation for annual wheat improvement, as a perennial forage crop with potential to be bred for grain production, and for utility in preventing soil and nutrient loss.  Hybrid lines made by crossing Thinopyrum species and Triticum aestivum (common wheat) can increase resilience of wheat to pathogens and abiotic stress and can improve the grain yield of the perennial crop.  However, lack of homology between Thinopyrum and Triticum species reduces genome stability, seed set, and perenniality. Fifty-three hybrid wheat-wheatgrass lines from the perennials Th. intermedium, Th. ponticum, and Th. junceum, crossed with the annuals T. aestivum, T. carthlicum, and T. turgidum, were developed at the Land Institute in Salina, KS.  Multiple plants of each line were evaluated for winter hardiness and perenniality, and screened for wheat stem rust (Puccinia graminis) and Fusarium head blight (F. graminearum) reaction.  Two lines showed perenniality in Minnesota and may be valuable as cold-tolerant perennial wheat germplasm.  Twenty-four of 48 hybrid lines were resistant to all stem rust races screened, including TTKSK (syn. Ug99), TRTTF, and common US races. Of the 30 hybrid lines point inoculated with F. graminearum, 21 were resistant based on percent of infected spikelets and percent visually scabby kernels. Three and four sources of potentially novel stem rust and FHB resistance, respectively were identified and may be useful for wheat improvement. Based on chromosome counts, seven lines representing two families showed genetic stability.