Submitted to: International Congress of Genetics Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/28/1998
Publication Date: N/A
Technical Abstract: Fusarium head blight (FHB), commonly called scab, is a devastating disease of wheat. The disease is caused by the fungus Fusarium graminearum, which infects wheat heads from flowering through grain fill, resulting in large losses (approaching a billion dollars in some years) due to loss in grain yield and quality. There is no reliable source of scab resistance in the current wheat cultivars. We have found that two wild relatives of wheat the tetraploid wheatgrass (Thinopyrum junceiforme; 2n = 4x = 28; J1J1J2J2 genomes) and diploid wheatgrass (Lophopyrum elongatum; 2n = 2x = 14; EE genome) are excellent sources of resistance to FHB. To transfer this resistance to durum wheat (Triticum turgidum; 2n=4x=28; AABB), we crossed two agronomically superior durum cultivars, Lloyd and Langdon, with the wild grasses. The synthetic Lloyd Th. junceiforme F1 hybrids (2n = 4x = 28; ABJ1J2) had a meiotic association of 0.09 IV + 0.35 III + 7.27 II + 12.05 I, and were sterile. By backcrossing the F1 hybrids to Lloyd we have produced several fertile hybrid derivatives which have the full chromosome complement of durum wheat plus a few chromosomes or chromosome segments of the wild junceiforme parent, as revealed by fluorescence in situ hybridization (FISH). FISH analysis has shown stable integration of alien chromatin into the durum genome. Langdon L. elongatum hybrid derivatives also showed integration of alien chromatin into the durum genome. Some of the Lloyd-junceiforme and Langdon-elongatum derivatives showed high resistance to FHB. With further backcrossing and selection it should be possible to produce genetically stable durum cultivars with high levels of FHB resistance. Wide hybridization offers an excellent means of breeding durum wheat for FHB resistance.