Document Type

Thesis - Open Access

Award Date

2019

Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology

First Advisor

Wanlong Li

Keywords

chromosome engineering, crop improvement, sea wheatgrass, tertiary genepool, wheat genetics, wild relatives

Abstract

Production of wheat is challenged by dynamic biotic and abiotic stresses. Genetic improvement via alien gene transfer is an effective approach to tackle such challenges. Alien gene transfer played an important role in the history of wheat crop improvement. Sea wheatgrass (SWG; Thinopyrum junceiforme, 2n = 28, genomes J1J1J2J2) is a wild relative of wheat. In our previous work, we have developed a complete amphiploid between cultivated emmer and SWG and shown that SWG is resistant to wheat streak mosaic virus, Fusarium head blight and wheat stem sawflies (due to the solid stem) and tolerant to waterlogging, salinity, heat, and low nitrogen. At the same time, we produced 433 BC2F1 and BC2F2 individuals by crossing hexaploid wheat and the amphiploid. Our objective of this thesis study was to develop the wheat-SWG chromosome addition lines. To identify and characterize alien chromosomes, we developed 127 SWG-specific markers using a draft SWG genome assembly. These markers were used to screen the BC2F1 and BC2F2 populations and characterize the SWG chromosomes carried by these lines. Combining the genomic in situ hybridization data from Dr. Steven Xu’s group (USDA ARS, Fargo), with whom we are collaborating, we were able to identify a complete set of wheat-SWG chromosome addition lines and characterize all SWG chromosomes. The addition lines developed in the present study will serve as the SWG chromosome library in the wheat background. They can be used to map and identify useful genes present in SWG genome. The addition lines will further be used in the development of translocation lines facilitating the alien introgression into the wheat genome. The molecular markers developed in our study will be useful in the subsequent steps of chromosome engineering and gene mapping.

Library of Congress Subject Headings

Wheat -- Genetics.
Wild wheats -- Genetics.
Wheatgrasses -- Genetics.
Genetic transformation.
Genetic markers.

Format

application/pdf

Number of Pages

97

Publisher

South Dakota State University

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Rights Statement

In Copyright