Enhancing wheat field performance and response to abiotic stress with novel growth-regulatory allelles

Lead Research Organisation: Rothamsted Research
Department Name: Unlisted

Abstract

The 'Green Revolution' dwarfing (Rht) alleles that increase wheat yields under high input conditions are orthologues of the Arabidopsis GAI gene and encode mutant DELLA proteins. DELLAs are repressors of plant growth that are degraded in the presence of gibberellin (GA) whereas the gai/Rht mutants are insensitive to GA. Most UK wheat varieties carry the semi-dwarfing Rht2 (Rht-D1b) allele but variation in height between genotypes suggests that other loci play a role in determining stature. We aim to identify these loci through co-localisation of quantitative stature traits identified in UK wheat germplasm with genes in the GA-DELLA pathway. Based on functional analyses in vitro and performance in the field alleles will be identified for use in wheat breeding.
Aims:
1. Identify genetic loci responsible for variation in wheat stem height in elite UK cultivars through co-localisation of genes encoding components of GA biosynthesis and signalling with height QTLs. Identify allelic sequence variation in GA-DELLA genes within this material. Develop intragenic, allele-specific markers for these loci and validate by crossing into elite germplasm.
2. Assess the utility of known alternative dwarfing alleles by introgression into modern, high-yielding backgrounds.
3. Assess the performance and stress tolerance of the introgressed alleles under controlled environment and field conditions for a range of characters including germination rate, seedling vigour, plant stature, straw strength, tillering, grain number and individual grain weights.

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