Thesis
Characterizing zak ERA8's seed dormancy, hormone response, endogenous hormone levels, agronomic traits, and quality traits
Washington State University
Master of Science (MS), Washington State University
2013
Handle:
https://hdl.handle.net/2376/103699
Abstract
Preharvest sprouting (PHS) is the germination on the mother plant under cool and wet conditions prior to harvest. PHS is a problem in cereals, like wheat, when the germination process begins to degrade the starch granules, resulting in low quality flour. PHS is associated with low seed dormancy; the inability of the seed to germinate even under favorable environmental conditions (moisture, temperature, light). Dormancy can be lost through afterripening, cold stratification, and scarification. Dormancy is also associated with sensitivity and accumulation of the plant phytohormone abscisic acid (ABA). This thesis studied the characteristics of the ABA hypersensitive wheat (Triticum aestivum L.) mutant, Zak ERA8 (Enhanced Response to ABA). An after-ripening time course in the presence and absence of exogenous ABA and gibberellic acid (GA), a plant hormone that stimulates germination, showed that Zak ERA8 had increased seed dormancy, increased ABA sensitivity, and decreased GA sensitivity compared to that of wild-type Zak. Further examination of endogenous levels of several plant hormones showed that ABA and Indole acetic acid (IAA) decreased with afterripening and imbibition, whereas GA and jasmonates (JA) increased during after-ripening. The Zak ERA8 mutation had lower levels of ABA and the inability to decrease IAA when the seed was dormant compared to Zak, suggesting that ERA8 may be a signaling mutant rather than a catabolic mutant. The increased seed dormancy also resulted in increased PHS tolerance v without compromising field emergence. Finally, the semi-dominant Zak ERA8 gene showed increased ABA hypersensitivity, but still produced similar agronomic and end-use quality traits in field trials as Zak wild-type. The mutation in Zak ERA8 could potentially be integrated into wheat breeding programs to increase dormancy and reduce preharvest sprouting susceptibility.
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Details
- Title
- Characterizing zak ERA8's seed dormancy, hormone response, endogenous hormone levels, agronomic traits, and quality traits
- Creators
- Shantel Amealia Martinez
- Contributors
- Camille M. Steber (Degree Supervisor)Arron H. Carter (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525073001842
- Language
- English
- Resource Type
- Thesis