Germplasm Enhancement and Chromosome Remodeling in Wheat Wide Hybridization

Plant breeding may lead to a narrowing of genetic diversity of cultivated crops, thereby affecting sustained selection gains in crop improvement. Germplasm enhancement is an important aspect of wheat genetics and breeding. Thinopyrum elongatum and Thinopyrum intermedium, the wild relatives of wheat, have been suggested as a potentially novel source of resistance to several major wheat diseases including Fusarium Head Blight (FHB). A series of wheat (cv. Chinese Spring, CS)-Th. elongatum addition, substitution and ditelosomic lines were assessed for resistance to FHB. The results indicated that the lines containing chromosome 7E of Th. elongatum gave a high level of resistance to FHB; the infection did not spread beyond the inoculated floret. Furthermore, it was determined that the novel resistance gene(s) of 7E was located on the short arm (7ES) based on a difference in FHB resistance between the two 7E ditelosomic lines. Th. ponticum, Th. intermedium and tetraploid Th. elongatum contained useful and potential genes for wheat improvement. Amphiploids and partial amphiploids were released from the hybrids between wheat and Thinopyrum, and their genome chromosomal constitution was revealed by using GISH and multicolor GISH.