ORCID Profile
0000-0003-2015-1650
Current Organisation
NSW Department of Primary Industries
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Publisher: MDPI AG
Date: 29-06-2022
Abstract: In crop improvement programs, hybrid vigour (heterosis) is an important breeding strategy but the molecular mechanisms of hybrid vigour are still unclear. Grain yield declines after F1 generation due to phenotypic segregation. We found that, at the early seedling stage in hybrids derived from the temperate japonica rice varieties ‘Doongara’ and ‘Reiziq’, hybrid vigour was approximately 40% greater than in the better parents. Inbred high-yielding lines (Hybrid Mimics) were developed from the ‘Doongara’ × ‘Reiziq’ F1 by selfing and recurrent selection for F1-like plants in the F2 through to the F5 generation. Grain yields are stable over subsequent generations in the Hybrid Mimic lines. The importance of photosynthesis in early seedling development was demonstrated. Photosynthesis-related genes were expressed in the hybrid earlier than in the parents physiological evidence using gas exchange indicated the early commencement of photosynthesis. Dark germination experiments supported the requirement for photosynthesis for early vigour in hybrids.
Publisher: Cold Spring Harbor Laboratory
Date: 28-08-2019
DOI: 10.1101/748368
Abstract: The disease scald of barley is caused by the pathogen Rhynchosporium commune and can cause up to 30-40% yield loss in susceptible varieties. In this study, the Australian barley cultivar Yerong was demonstrated to have resistance that differed from Turk ( Rrs1 ) based on seedling tests with 11 R. commune isolates. A doubled haploid population with 177 lines derived from a cross between Yerong and Franklin was used to identify quantitative trait loci (QTL) for scald resistance. Scald resistance against four pathogen isolates was assessed at the seedling growth stage in a glasshouse experiment and at the adult growth stage in field experiments with natural infection over three consecutive years. A QTL on chromosome 3H was identified with large effect, consistent with a major gene conferring scald resistance at the seedling stage. Under field conditions, scald percentage was negatively correlated with early relative maturity. A bivariate analysis was used to model scald percentage and relative maturity together, residuals from the regression of scald percentage on relative maturity were used as our phenotype for QTL analysis. This analysis identified one major QTL on chromosome 3H, which mapped to the same position as the QTL identified for scald resistance at seedling stage. The identified QTL on 3H is proposed to be different from the Rrs1 on the basis of seedling resistance against different R. commune isolates and physical map position. The analysis also identified an additional novel QTL on chromosome 7H. This study increases the current understanding of scald resistance and identifies genetic material possessing QTLs useful for the marker-assisted selection of scald resistance in barley breeding programs.
Publisher: Springer Science and Business Media LLC
Date: 29-08-2017
DOI: 10.1007/S00122-017-2969-2
Abstract: Water-soluble carbohydrate accumulation can be selected in wheat breeding programs with consideration of genetic × environmental interactions and relationships with other important characteristics such as relative maturity and nitrogen concentration, although the correlation between WSC traits and grain yield is low and inconsistent. The potential to increase the genetic capacity for water-soluble carbohydrate (WSC) accumulation is an opportunity to improve the drought tolerance capability of rainfed wheat varieties, particularly in environments where terminal drought is a significant constraint to wheat production. A population of elite breeding germplasm was characterized to investigate the potential for selection of improved WSC concentration and total amount in water deficit and well-watered environments. Accumulation of WSC involves complex interactions with other traits and the environment. For both WSC concentration (WSCC) and total WSC per area (WSCA), strong genotype × environment interactions were reflected in the clear grouping of experiments into well-watered and water deficit environment clusters. Genetic correlations between experiments were high within clusters. Heritability for WSCC was larger than for WSCA, and significant associations were observed in both well-watered and water deficit experiment clusters between the WSC traits and nitrogen concentration, tillering, grains per m
Publisher: Wiley
Date: 14-06-2020
DOI: 10.1111/MPP.12945
Publisher: Springer Science and Business Media LLC
Date: 07-04-2023
DOI: 10.1007/S00122-023-04305-1
Abstract: The inclusion of multiple traits and multiple environments within a partially separable factor analytic approach for genomic selection provides breeders with an informative framework to utilise genotype by environment by trait interaction for efficient selection. This paper develops a single-stage genomic selection (GS) approach which incorporates information on multiple traits and multiple environments within a partially separable factor analytic framework. The factor analytic linear mixed model is an effective method for analysing multi-environment trial (MET) datasets, but has not been extended to GS for multiple traits and multiple environments. The advantage of using all information is that breeders can utilise genotype by environment by trait interaction (GETI) to obtain more accurate predictions across correlated traits and environments. The partially separable factor analytic linear mixed model (SFA-LMM) developed in this paper is based on a three-way separable structure, which includes a factor analytic matrix between traits, a factor analytic matrix between environments and a genomic relationship matrix between genotypes. A diagonal matrix is then added to enable a different genotype by environment interaction (GEI) pattern for each trait and a different genotype by trait interaction (GTI) pattern for each environment. The results show that the SFA-LMM provides a better fit than separable approaches and a comparable fit to non-separable and partially separable approaches. The distinguishing feature of the SFA-LMM is that it will include fewer parameters than all other approaches as the number of genotypes, traits and environments increases. Lastly, a selection index is used to demonstrate simultaneous selection for overall performance and stability. This research represents an important continuation in the advancement of plant breeding analyses, particularly with the advent of high-throughput datasets involving a very large number of genotypes, traits and environments.
Publisher: Cold Spring Harbor Laboratory
Date: 30-06-2022
DOI: 10.1101/2022.06.29.498182
Abstract: Septoria tritici blotch (STB) has been ranked the third most important wheat disease in the world, threatening a large area of wheat production. Although major genes play an important role in the protection against Zymoseptoria tritici infection, the lifespan of their resistance unfortunately is very short in modern agriculture systems. Combinations of quantitative resistance with minor effects, therefore, are believed to have prolonged and more durable resistance to Z. tritici . In this study new quantitative trait loci (QTLs) were identified that are responsible for seedling-stage resistance and adult-plant stage resistance (APR). More importantly was the characterisation of a previously unidentified QTL that can provide resistance during different stages of plant growth or multi-stage resistance (MSR). At the seedling stage, we discovered a new isolate-specific QTL, QSt.wai.1A.1. At the adult-plant stage, the new QTL QStb.wai.6A.2 provided stable and consistent APR in multiple sites and years, while the QTL QStb.wai.7A.2 was highlighted to have MSR. The stacking of multiple favourable MSR alleles was found to improve resistance to Z. tritici by up to 40%. An Australian GWAS panel discovered three new QTLs associated with seedling-stage resistance, adult-plant stage resistance, and multi-stage resistance, respectively.
No related grants have been discovered for Ben Ovenden.