2012 Annual Report
1a.Objectives (from AD-416):
A major goal of wheat improvement is to identify, isolate, and characterize genes and gene complexes that control value-added traits that can be introduced into commercial cultivars to improve production. Historically, once such gene complexes were identified and characterized they were manipulated into a hexaploid wheat background for improved production. Once the options for trait improvement genes in the available wheat germplasm were exhausted wheat geneticists turned to other members of the Triticeae tribe (cereals) as desirable genetic resources for trait exploitation. However, to date only a few gene complexes from non-wheat related species and genera have been characterized, manipulated and introduced into wheat. The lack of advancement in this area results from an undesirable linkage drag, resulting in low yields, that is associated with the transference of gene complexes from related species. This laboratory has developed methods for the efficient transferring of value-added gene complexes, without linkage drag, from rye into wheat for wheat improvement. This project will utilize these previously developed technologies of chromosomal centric-break and fusion translocations to transfer the value added traits of disease resistance and abiotic stress tolerance from rye and wheat-rye hybrids (triticales) to commercially useful hexaploid wheat cultivars. In particular the project will focus on 1. Identifying novel genetic elements associated with resistance to new strains of stem rust linked to rye chromosome 1R within local and world stock collections of triticales and spring ryes for transfer into hexaploid wheat, and 2. Identifying, characterizing and transferring novel genetic elements, regardless of chromosomal location, for resistance to stem and leaf rusts and tolerance to low pH and saline soils for transfer into hexaploid wheat. Objective 1: Develop, evaluate, and distribute wheat-rye aneuploid stocks. Objective 2: Use rye genes and gene complexes to improve stem and leaf rust resistance and abiotic stress tolerance in wheat.
1b.Approach (from AD-416):
To create and characterize wheat containing 1RS/1BL wheat/rye translocations. The present discovery-driven objective was designed to screen all newly developed wheat/rye translocation stocks, from every rye chromosome arm, for resistance to new races of leaf and stem rust, as well as screen for new levels of tolerance to select abiotic stresses.
All of the genetic stocks generated during the year and those derived from earlier studies were fully characterized and increased for storage in the stock collection. All of the requests for the generated stocks were processed and copies of the major collections were sent to appropriate facilities within ARS for further maintenance and development. All backcrossing schemes into hexaploid wheat stocks were completed for the newly developed triticales lines with leaf/stem rust resistance and aluminum toxicity tolerance. The 1RS wheat/rye translocation stocks were sent to ARS stock collections for distribution to public breeding programs.