Seed vigour tests enable detection of seedlots with high field emergence and storability. Here, an accelerated aging (AA) protocol is proposed as a seed vigour test for predicting field emergence of wet direct-seeded rice (Oryza sativa) seeds. Seeds of 10 rice varieties, eight with intermediate bold grain type and two with short round grain type, harvested in 2017 were subjected to AA at temperatures of 40–45°C for periods of 24–120 h, or to standard seed germination at 25°C, followed by emergence testing in a rice field. AA treatments that were found to be appropriate to predict field emergence in 2017 were repeated with the same varieties harvested in 2018. Standard seed germination could not predict field emergence of tested rice varieties (r <0.2, α = 0.01). The appropriate AA treatment to predict field emergence was dependent on the grain type. AA treatment 43°C/72 h was found to be the best for predicting field emergence of wet direct-seeded rice of intermediate bold grain type (r >0.8, α = 0.01). Further studies are needed to find the best AA test for predicting field emergence of varieties of short round grain type.

It is largely known that low temperature stress can affect rice (Oryza sativa L.) development and yield. However, most studies have focussed on unique and uninterrupted cold treatment, which is not representative of cold conditions for early sowing in temperate and subtropical areas where cold nights are followed by warm days during early vegetative stages. In order to elucidate whether rice plants could recover from the damages caused by repetitive cold nights, we submitted a cold-tolerant (CT) and a cold-sensitive (CS) indica genotype to 28 cold nights (10°C) followed by warm days (26°C) and analysed the developmental and productivity traits of plants cultivated in greenhouse and field conditions. While CT plants were able to recover from cold damage without significant development and seed production penalties, CS plants were affected, presenting lower results in plant height, tiller number, number of seeds per plant, % of full seeds per plant, grain length and area, weight of 1000 full grains, and grain weight per plant, with a grain yield reduction of 82% and 30% when cultivated in greenhouse and field conditions, respectively. Such data on sowing period, night temperatures and the cold response of the rice cultivar used are important for the producer to consider.

Synthesis and analysis of past cropping research can provide valuable information to direct future decisions around crop management. Systematic reviews and meta-analyses are considered gold standards in the synthesis and analysis of scientific research because they distil large amounts of information about complex issues, provide a summary of knowledge to date, and identify knowledge gaps. However, several issues concerning the methodologies employed to conduct systematic reviews have been identified; among them is the risk of publication bias when a review relies too heavily on ‘white’ literature from published academic sources and in so doing fails identify relevant ‘grey’ literature. Grey literature is inherently difficult to identify and collect, but forms a large portion of information available in many fields including agricultural-based research within Australia. The Online Farm Trials (OFT) database is a digital database of crop research field trial data from across Australia that has the potential for use as a discipline-specific source of grey literature to inform systematic reviews and meta-analyses. Using a case study approach to investigate the amount of information available on time of sowing (sowing date) on crop yield across Australia, we demonstrate that the OFT database provides easy access to transparent and reproducible search results similar to other commonly used academic databases.

Productivity of chickpea (Cicer arietinum) under current climatic conditions is severely limited by water deficit and high temperatures, either alone or in combination. Breeding for improved tolerance, and increasing understanding of the physiological and biochemical mechanisms underlying tolerance, are imperative for achieving yield stabilisation. We evaluated 36 chickpea genotypes including 21 interspecific derivatives (from the cross C. arietinum ICCV96030 × C. pinnatifidum IC525200), their parents, 10 elite genotypes, and three checks (drought tolerant, heat tolerant, drought and heat susceptible) under three environments: timely sowing with irrigation, timely sowing with drought stress, and late sowing leading to heat stress. Four parameters were considered: seed yield, proline content, membrane permeability index, and relative leaf water content. Although the average seed yield plummeted under both stresses, the impact of high temperature was more pronounced. Mean leaf water content declined, whereas membrane permeability index and proline content increased, under both stresses. Leaf water content showed a significant positive correlation with seed yield under all environments, and thus can be employed as an early-stage screening strategy in breeding programs for developing stress tolerant genotypes. Based on estimated stress susceptibility indices for seed yield, derivative line GLW605 was identified as a promising donor for both drought and heat tolerance. Additionally, three derivative lines (GLW607, GLW649, GLW677) were found tolerant to drought, and one derivative line (GLW669) showed tolerance to heat alone. Yield levels of the identified lines were statistically on par with respective tolerant checks. Results suggest that tolerance to drought and heat was successfully introgressed from the wild species, C. pinnatifidum, into the cultivated background. The promising derivative lines can be employed for developing multi-stress tolerant cultivars.

Barley (Hordeum vulgare L.) is one of the most used species for hydroponic green fodder. The chemical properties of fodders may be enhanced through use of various strategies during crop production, including stress applications. In this context, hydrogen peroxide (H₂O₂) is used as a stress factor in controlled elicitation, a technique used to increase secondary metabolites in food. The aim of this research was to evaluate the possibility of using controlled elicitation with H₂O₂ for enhancing the chemical properties of hydroponic barley fodder. H₂O₂ was applied to the seeds as a pre-germination treatment at three concentrations: 50, 100 and 150 mM. Morphological changes, enzymatic defence-related activities (superoxide dismutase, catalase, chalcone isomerase, phenylalanine ammonia-lyase), total phenolics content, and antioxidant capacity were evaluated. Significant increases in total phenolics content, phenylalanine ammonia-lyase activity and ABTS antioxidant capacity were obtained when seeds were treated with 50 mM H₂O₂. Plant growth was promoted with 100 mM and 150 mM H₂O₂ treatments, and germination of seeds with 100 mM H₂O₂. It was established that controlled elicitation using H₂O₂ increased some morphological and biochemical variables of hydroponic barley fodder related to food properties.

Phalaris aquatica L. (phalaris) is a cool-season perennial grass originating from the Mediterranean Basin, north-west Africa and Middle Eastern regions that is used for livestock agriculture mainly in temperate areas with dry summers. It has been the subject of breeding programs in Australia, South America, New Zealand and the USA. Increased knowledge of relationships between wild and cultivated germplasm through use of molecular markers has the potential to facilitate future breeding gains. For this purpose, we conducted an analysis of P. aquatica by using 3905 polymorphic DArTseq SNP markers. Genetic diversity as measured by expected heterozygosity was similar for wild (H_E = 0.14; n = 57) and cultivated (H_E = 0.13; n = 37) accessions. Diversity in wild germplasm was generally continuous in nature, largely related to geographical location, with a division at the broadest scale into eastern and western clades, with more admixture in the western than the eastern clade. Structure analysis of wild germplasm indicated six subpopulations consistent with country of origin, with some admixture among subpopulations likely resulting from natural and human influences. There were nine subpopulations among wild and cultivated accessions combined. This population structure should be considered if genomic selection is applied in P. aquatica. Analysis of molecular variance indicated that 71% of the genetic variation occurred within subpopulations and 29% among subpopulations. Genetic distances were low among cultivated germplasm from most countries except the USA, which was more distinct. Evaluation of material from the US pool by breeding programs in other countries, and additional material from the less utilised eastern clade, may be worthwhile.

Changes in grazing intensity affect forage production and performance of animal on C₄ grass pastures; however, these relationships are not well defined for cattle grazing on limpograss (Hemarthria altissima (Poir) Stapf & C.E. Hubb. cv. Flórida) under continuous stocking. The objective of this study was to quantify plant and animal production from Flórida limpograss pastures, managed at different grazing intensities by beef heifers (i.e. different sward heights) in order to define pasture management outcomes that maximise plant and animal responses. For a 3-year period, the influence exerted by the sward height (10, 20, 30 and 40 cm) was assessed. Greater total herbage accumulation and herbage accumulation rate were observed for the more lenient grazing heights (30 and 40 cm). The 20-, 30- and 40-cm heights revealed similar heifer average daily gain of 0.49 kg liveweight (LW) animal^–1 day^–1, reducing at the rate of 0.04 kg LW animal^–1 day^–1, for each cm decrease below 19 cm, according to a segmented equation. LW gain per area showed a quadratic response to the sward height, with optimum values (i.e. 2.1 kg LW ha^–1 day^–1) achieved at a pasture height of around 21 cm. Therefore, to optimise cattle performance on continuously stocked Flórida limpograss pastures, a sward height of ∼20 cm should be maintained.

Tithonia diversifolia (Mexican sunflower) is a shrub used for animal feed that has outstanding agronomic and chemical characteristics. Its potential to modify the dynamics of fermentation and improve the supply of nutrients to ruminants has received considerable attention. This study was designed to determine the effect of different genotypes of T. diversifolia on ruminal fermentation and degradation of dry matter (DM), concentration of volatile fatty acids, and production of methane (CH₄) when mixed with a low-quality tropical grass, Urochloa brizantha (palisade grass). In a randomised complete block design, mixtures of seven genotypes of T. diversifolia with U. brizantha cv. Marandú were evaluated by using the in vitro gas production technique. The effect of fertilisation was also evaluated for each genotype. Inclusion of T. diversifolia significantly (P < 0.05) increased the supply of nutrients and modified fermentation parameters. DM degradation of biomass after 72 h was greater in the presence of T. diversifolia than for feeds based only on U. brizantha (68.0% vs 63.4%; P < 0.01). CH₄ production was lower (P < 0.05) during fermentation with some T. diversifolia genotypes (25.3 vs 27.7 mg CH₄ g^–1 incubated DM), and the acetic:propionic acid ratio was also lower. Fertilisation of T. diversifolia genotypes increased DM degradation, increased the content of certain nutrients (e.g. crude protein) and modified CH₄ production. Therefore, inclusion of T. diversifolia in mixtures based on low-quality tropical grasses such as U. brizantha increases the supply of nutrients (crude protein, minerals, energy) and can modify the products of enteric fermentation, with some genotypes decreasing enteric CH₄ emissions.