Thesis
Phenotypic and genotypic studies of red seed coat color in wheat (Triticum aestivum L.)
Washington State University
Master of Science (MS), Washington State University
07/2013
DOI:
https://doi.org/10.7273/000006228
Abstract
Red seed coat color in wheat is controlled by dominant R loci, three homoeologous genes located on the long arms of chromosomes 3A (R-A1), 3B (R-B1) and 3D (R-D1). Color variation has been found to be dependent on the number of R1 homoeoalleles, and also on environmental factors. Seed samples are inspected as part of the seed certification process, for presence and number of seeds exhibiting off-type coloring. This test is conducted using a sodium hydroxide (NaOH) test, which magnifies color differences. Exceeding specified limits results in a loss of certification, possible reduction in market grade, and a corresponding loss of profit. The occurrence of color off-type seeds is therefore a cause of concern for all parties involved in seed production. Normal and suspected off-type seeds from certified varieties were digitally photographed, grown, and genotyped at the R1 homoeoloci. Additional genetic marker analysis was completed to determine variety purity. Results indicated three primary sources, or reasons, for seeds of off-type color: contamination from genetically different varieties, color variation due to environmental factors, and varieties that are heterogeneous at one or more R1 homoeolocus, indicating heterozygosity. These findings highlight the precaution and care needed at every step of the breeding and seed production processes to limit contamination. Additionally, work was done to modify the NaOH test. NaOH is a strong base and when imbibed by the seed, germination is greatly reduced. This prevents further genetic or phenotypic inspection of the seed, which is not optimal in finding sources of variation. Here a less lethal, modified sodium hydroxide test is proposed.
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Details
- Title
- Phenotypic and genotypic studies of red seed coat color in wheat (Triticum aestivum L.)
- Creators
- Caleb Carbine Squires
- Contributors
- Arron Hyrum Carter (Chair) - Washington State University, Department of Crop and Soil SciencesMICHAEL O. PUMPHREY (Committee Member) - Washington State University, Department of Crop and Soil SciencesDeven Robert See (Committee Member) - Washington State University, Department of Plant PathologyCraig F Morris (General Contributor)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Crop and Soil Sciences
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 82
- Identifiers
- 99901081339901842
- Language
- English
- Resource Type
- Thesis