Biology subjects

Boden, S. A.

Publications and source records attributed to Boden, S. A..

4 recordsLinked to original sources

bioRxiv2025

Mutations in HOMEOBOX DOMAIN-2 improve grain protein content in wheat without significantly affecting grain yield and senescence

MicroRNA-resistant alleles of HOMEOBOX DOMAIN-2 (HB-2) were recently reported to improve grain protein content (GPC) in wheat by modifying vascular development in stems to increase amino acid distribution to grain. However, it is not known if these alleles increase GPC at the expense of other physiologically important traits, such as senescence and yield-component traits. Here, we evaluated the effects of mutations in HB-2 on grain yield and nitrogen (N)-use efficiency as well as senescence and plant architecture in multi-environment glasshouse and field experiments. In glasshouse experiments, the mutations in HB-2 moderately improved GPC irrespective of N supply and without accelerating senescence or decreasing grain number or weight compared to the wildtype spring wheat cv. Cadenza. The trait analysis indicated mutant plants were more tolerant of N limitation in terms of above-ground N reduction compared to the wild type. The expression of all HB-2 homeologues increased in spikes at the lemma primordium stage in response to N limitation, indicating the later GPC increase could be a result of enhanced N sink strength determined during early development, rather than processes caused by direct changes in HB-2 expression in the grain. In field experiments, the introgression of HB-2 alleles into Australian elite spring wheat cultivars significantly improved GPC without compromising grain yield. The outcomes of this study support the introduction of miRNA-resistant HB-2 alleles, with a preference to HB-A2, into commercial wheat for improving grain quality without a yield penalty.

plant biology↗

bioRxiv2024

Stigma longevity is not a major limiting factor in hybrid wheat seed production

Hybrids offer a promising approach to improve crop performance because the progeny are often superior to their parent lines and they outyield inbred varieties. A major challenge in producing hybrid progeny in wheat, however, lies in the low outcrossing rates of the maternal parent. This is often attributed to suboptimal synchronisation of male and female flowering as delayed pollination can result in reproductive failure due to female stigma deterioration. To test this accepted dogma, we examined the seed set capacity of six male sterile (MS) cultivars, each varying in the onset of stigma deterioration. To mimic a hybrid seed production scenario, MS cultivars were grown during two consecutive field seasons, and open pollination was allowed up to 15 days after flowering of the female parent using a blend of seven male fertile cultivars with varying flowering times. Detailed analysis of the temporal and spatial distribution of hybrid seed set along the spike across the six MS cultivars showed that grain production remained remarkably stable during the pollination window tested. These findings suggest sustained receptivity of stigma to pollen across all tested MS cultivars throughout the entire time course. We therefore conclude that stigma longevity does not represent a limiting factor in hybrid wheat seed production, and that breeding efforts should prioritise the study of other female traits, such as enhanced access to airborne pollen.

plant biology↗

bioRxiv2020

Step-wise increases in FT1 expression regulate seasonal progression of flowering in wheat (Triticum aestivum L.)

ABSTRACTFlowering is regulated by genes that respond to changing daylengths and temperature, which have been well-studied using controlled conditions; however, the molecular processes underpinning flowering in nature remain poorly understood. Here, we investigate the genetic pathways that coordinate flowering and inflorescence development of wheat as daylengths extend naturally in the field, using lines that contain variant alleles for the key photoperiod gene, Photoperiod-1 (Ppd-1). We found flowering involves a step-wise increase in the expression of FLOWERING LOCUS T1 (FT1), which initiates under day-neutral conditions of early spring. The incremental rise in FT1 expression is overridden in plants that contain a photoperiod-insensitive allele of Ppd-1, which hastens the completion of spikelet development and accelerates flowering time. The accelerated inflorescence development of photoperiod-insensitive lines is promoted by advanced seasonal expression of floral meristem identity genes. The completion of spikelet formation is promoted by FLOWERING LOCUS T2, which regulates spikelet number and is activated by Ppd-1. In wheat, flowering under natural photoperiods is regulated by step-wise increases in the expression of FT1, which responds dynamically to extending daylengths to promote early inflorescence development. This research provides a strong foundation to improve yield potential by fine-tuning the photoperiod-dependent control of inflorescence development.Competing Interest StatementThe authors have declared no competing interest.View Full Text

plant biology↗

bioRxiv2017

Speed breeding: a powerful tool to accelerate crop research and breeding

The growing human population and a changing environment have raised significant concern for global food security, with the current improvement rate of several important crops inadequate to meet future demand [1]. This slow improvement rate is attributed partly to the long generation times of crop plants. Here we present a method called speed breeding, which greatly shortens generation time and accelerates breeding and research programs. Speed breeding can be used to achieve up to 6 generations per year for spring wheat (Triticum aestivum), durum wheat (T. durum), barley (Hordeum vulgare), chickpea (Cicer arietinum), and pea (Pisum sativum) and 4 generations for canola (Brassica napus), instead of 2-3 under normal glasshouse conditions. We demonstrate that speed breeding in fully-enclosed controlled-environment growth chambers can accelerate plant development for research purposes, including phenotyping of adult plant traits, mutant studies, and transformation. The use of supplemental lighting in a glasshouse environment allows rapid generation cycling through single seed descent and potential for adaptation to larger-scale crop improvement programs. Cost-saving through LED supplemental lighting is also outlined. We envisage great potential for integrating speed breeding with other modern crop breeding technologies, including high-throughput genotyping, genome editing, and genomic selection, accelerating the rate of crop improvement.

plant biology↗