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Document Type

Dissertation - University Access Only

Award Date


Degree Name

Doctor of Philosophy (PhD)

Department / School

Plant Science

First Advisor

Jose Gonzalez


Bread wheat (Triticum aestivum L.) is the most widely cultivated crop in the world and provides more than 20% of the food calories consumed by humans. The Orange Wheat Blossom Midge (OWBM), Sitodiplosis mosellana, is a destructive insect pest of wheat. Resistant cultivars, in particular those with resistance gene Sm1 are useful in managing this pest. The first objective of this research was to develop tools for future cloning of the Sm1 locus including the development of a linkage map of the wheat 2BS chromosome arm and the DNA delimiting the Sm1 locus. Several Simple Sequence Repeats (SSR) and KBiosciences competitive allele specific PCR (KASP) Single Nucleotide Polymorphism (SNP) markers were screened on CAP19 and CAP20, susceptible and resistant doubled haploid wheat lines, respectively; however, a linkage map was not developed due to insufficient polymorphism between the parents. Another larger mapping population of 677 recombinant inbred lines (RILs) was developed by using one resistant line ‘NDSU-24’ from the previous population and crossing it to Reeder (susceptible line) which can be used in the future to fine map the Sm1 gene. The second objective was to characterize changes in gene expression in resistant and susceptible plants challenged with the OWBM. Transcript Assemblies (TAs) encoding for enzymes or proteins involved in phenylpropanoid pathway, cell wall and lipid xiv metabolism, carbohydrate metabolism and phytohormones were among the TAs with larger changes in expression. This study should provide a foundation for further research into molecular mechanisms of resistance to OWBM, and possibly lead to better management of the resistance sources.

Library of Congress Subject Headings

Wheat -- Disease and pest resistance -- Genetic aspects
Sitodiplosis mosellana
Wheat -- Genetics


Includes bibliographical references



Number of Pages



South Dakota State University



Rights Statement

In Copyright