ARS | Publication request: TOWARD TRANSFERRING SCAB RESISTANCE FROM A DIPLOID WILD GRASS, LOPHOPYRUM ELONGATUM, INTO DURUM WHEAT

Submitted to: National Fusarium Head Blight Forum Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 14, 2000
Publication Date: December 10, 2000
Citation: Jauhar, P.P., Peterson, T.S. 2000. Toward transferring scab resistance from a diploid wild grass, lophopyrum elongatum, into durum wheat. National Fusarium Head Blight Forum Proceedings, p. 201-204.

Interpretive Summary: Scab or Fusarium head blight is a serious disease of durum wheat. A wild grass relative of wheat, named Lothopyrum elongatum, is highly resistant to scab. To transfer this scab resistance to durum wheat, we crossed some commercial durum cultivars with the wild grass. Although the hybrids were sterile, we produced several hybrid derivatives with high seed fertility, and screened them for scab resistance. Several of the hybrid derivatives, with one or more chromosomes from the grass parent, showed high resistance. Using a sophisticated technique, called fluorescent in situ hybridization, we were able to distinguish the grass chromosomes from wheat chromosomes. Our efforts are focused on stabilizing the chromosome number and retaining scab resistance in our hybrid derivatives.

Technical Abstract: Scab or Fusarium head blight is a serious disease of wheat. Because diploid wild grass, Lophopyrum elongatum (2n = 2x = 14; EE genome) is highly resistant to scab, we crossed some commercial durum cultivars with this grass. The F1 hybrids were sterile. We produced, by backcrossing to the recurrent durum parent followed by selfing, several hybrid derivatives with 80% or higher seed fertility. These hybrid derivatives were screened for scab resistance. The hybrid material with one or more grass chromosomes showed high resistance to scab (less than 21% infection). However, on subsequent backcrossing and selfing, the hybrid derivatives progressively lost chromosomes of the grass parent and hence lost the level of resistance. Using fluorescent in situ hybridization, we characterized the chromosomes of the promising hybrid derivatives. Our efforts are now focused on chromosomally stabilizing the hybrid derivatives and at the same time retaining scab resistance.