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United States Department of Agriculture

Agricultural Research Service

Research Project: Cytogenetic Manipulation of Durum Wheat for Resistance to Biotic and Abiotic Stresses and Enhanced End-Use Quality Project Number: 5442-21000-038-00
Project Type: Appropriated

Start Date: Apr 08, 2013
End Date: Sep 30, 2014

Objective:
The main objective of this research project is to develop durum germplasm with enhanced tolerance to FHB, using wild relatives as sources of resistance. We will be using the two diploid wheatgrasses, Lophopyrum elongatum and Thinopyrum bessarabicum. Durum material with improved processing and nutritional quality and tolerance to abiotic stresses will also be developed. Objective 1: Develop durum wheat genetic stocks with improved tolerance to Fusarium head blight, using wild relatives as sources of FHB resistance. Sub-objective 1a. Develop alien disomic addition and substitution lines involving desirable chromosomes of L. elongatum and Th. bessarabicum. Sub-objective 1b. Incorporate alien chromatin into the durum genome through homoeologous pairing between the alien and durum chromosomes by manipulating (suppressing)the Ph1 gene. Sub-objective 1c. Characterize alien chromatin incorporated into the durum genetic stocks using cytological and molecular tools. Objective 2: Develop durum wheat genetic stocks with improved processing and nutritional quality, and enhanced tolerance to abiotic stresses derived from wild relatives.

Approach:
Durum wheat (Triticum turgidum L., 2n = 4x = 28; AABB genomes) is an important cereal used for human consumption worldwide. It is widely grown in the northern plains area of the U.S. Fusarium head blight (FHB), or scab, is a ravaging fungal disease of wheat and causes huge losses. Because current durum cultivars have little or no FHB resistance we are using wild relatives, in the secondary/tertiary gene pool, as donors of resistance. Diploid wheatgrasses, Lophopyrum elongatum (2n = 2x = 14; EE genome) and Thinopyrum bessarabicum (2n = 2x = 14; JJ genome) are excellent sources of FHB resistance, and abiotic stresses. We released in 2008 a FHB-tolerant durum disomic addition line by adding chromosome 1E of L. elongatum to T. turgidum. We plan to produce more addition lines for other individual alien chromosomes and screen them for FHB-resistance. Alien disomic substitution lines will facilitate integration of desirable chromatin from the added chromosome into the durum complement. Chromosome pairing in durum wheat and its hybrids is precisely regulated and alien chromosomes do not pair with the corresponding wheat chromosomes. To induce integration of alien chromatin in the wheat genome, we plan to remove or inactivate the pairing regulating Ph1 gene in the hybrid derivatives. Chromosome-specific molecular markers and fluorescent genomic in situ hybridization (fl-GISH) will be employed to characterize alien chromosome/chromatin integration into the durum genome. The desirable genetic stocks having alien chromatin will also be tested for tolerance to abiotic stresses, and improved nutritional and end-use quality.

Last Modified: 10/24/2014
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