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Identification of gene-gene and gene-environment interactions for flowering time and grain yield using a multi-parental mapping population in barley

Dang, Hoang Viet (2021) Identification of gene-gene and gene-environment interactions for flowering time and grain yield using a multi-parental mapping population in barley. PhD thesis, Murdoch University.

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Abstract

Grain yield improvement is considered the key target for many cereal breeding programs. In barley, grain yield is closely associated with flowering time, which provides crops with the opportunity to avoid stress and to best utilise available environmental resources. In this study, major genes associated with flowering time were identified using a multiparent advanced generation intercross (MAGIC) population constructed from four commercial barley cultivars (Compass, GrangeR, La Trobe and Lockyer). Gene-specific markers were developed for fast-screening of phenology genes in 1,919 MAGIC recombinant inbred lines using Kompetitive allele-specific PCR (KASP) assays. Sequencing data revealed a novel mutation in the Gibberellin 20 oxidase 2 (HvGA20ox2) region in cv. Lockyer, which showed similar impacts on flowering time and plant height compared to the well-known semi-dwarf 1 (sdw1) gene. Analyses using gene-specific genotype data and phenotype data from field trials with differing sowing locations and times confirmed the association of the major genes HvGA20ox2, Photoperiod 1 (HvPPD-H1), Dense and erect panicle 1 (HvDEP1) and Flowering locus T 1 (HvFT1) with flowering time. Different combinations of these phenology genes showed a broader range in flowering time compared to the four parental lines. Novel gene combinations showed up to 7 days earlier in flowering time compared to the earliest parental cultivar (La Trobe), and 5 days later than the latest parental cultivar (Lockyer). The phenotype data from Corrigin and Esperance trials suggested that gene combinations for optimal flowering time might differ in these locations. Optimal gene combinations are estimated to result in up to 24% improved grain yield compared to the parental cultivars. The results from this study will benefit the development of higher-yielding and better-adapted barley cultivars for various growing conditions across Australia.

Item Type: Thesis (PhD)
Murdoch Affiliation(s): Agricultural Sciences
Centre for Crop and Food Innovation
Food Futures Institute
United Nations SDGs: Goal 12: Responsible Consumption and Production
Supervisor(s): Li, Chengdao and Hill, Camilla
URI: http://researchrepository.murdoch.edu.au/id/eprint/62713
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