Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.632864
Title: The roles of nitrogen and gibberellin metabolism in the control of stature in wheat
Author: Gallova, Barbora
ISNI:       0000 0004 5363 594X
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2014
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Abstract:
The Green Revolution introduced wheat varieties containing semi-dwarfing genes (Rht) that encode gibberellin (GA)-insensitive forms of the growth-repressing DELLA proteins, conferring improved resistance to lodging and improved harvest index. Reduction in the use of nitrogen (N) fertilizers is required to minimise environmental damage. Since most Rht varieties have been selected under high N inputs, new semi-dwarfing alleles may need to be developed. The response of tall, semi-dwarf and dwarf lines of wheat to N rate was examined in the field, but failed to provide evidence of higher N -responsiveness of rht tall varieties compared to Rht-1 semi-dwarfs and dwarfs. Expression of GA biosynthetic and signalling genes was monitored in elongating stems in field and controlled environment conditions under different N and water regimes. Although peduncle GA levels were reduced under N stress, there was no evidence that the effect of N supply on stature was directly mediated by changes in the transcription level ofGA metabolic genes. GA-biosynthetic genes were assessed as novel sources of dwarfism that may respond differently to environmental stresses such as N supply. A number of TILLING lines carrying mutations in the three homoeologues of GA20ox1 were crossed in order to generate combinations of mutant alleles. Triple knock-out plants from four combinations of alleles were identified by KASP genotyping assay in the F2 generation and all plants from the segregating populations were assessed for final height. There was a correlation between the genotypes and height, with triple knockouts being the shortest and wild types the tallest. Data from an F 3 population of the a1b.b1b.d1c genotype confirmed this observation and showed that reduced-height mutants maintained the same grain size and number as the wild-type plants. Therefore GA200xi may be classified as a novel wheat semi-dwarfing gene with potentially beneficial effects on height reduction without negatively affecting yield.
Supervisor: Not available Sponsor: Biotechnology and Biological Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.632864  DOI: Not available
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