To extend the production base of durum wheat in Australia, field trials were conducted on seven registered durum varieties across four seasons and six sites in locations where irrigation was supplied during crop growth. The purpose was to determine if the quality of the grain produced met the requirements for good milling and pasta-making quality and to understand the genotype, environment and their interaction in affecting yield and technological quality of the grain and derived pasta. High grain yields and grain protein were obtained, producing large grain weights, low screenings and low percentage of hard vitreous kernels. Yellow colour of semolina and pasta was reduced marginally but dough and other pasta technological characteristics were similar to typical dryland durum production, with some exceptions. Varieties were identified with potential for production under irrigation.

Bacillus subtilis strain GB03 has been shown to confer salt tolerance in Arabidopsis thaliana. In this study, the potential for GB03 to promote biomass accumulation and increase salt tolerance was investigated in wheat (Triticum aestivum). Soil-grown wheat seedlings were assayed for dry-weight increase. Endogenous Na and K contents were determined in plants with or without soil inoculation with GB03 along with 0, 25 or 100 mm NaCl solution added to the soil. We demonstrated that the introduction of GB03 in the soil triggered wheat biomass accumulation. Furthermore, GB03 improved salt tolerance as measured by increased tissue mass, lower Na accumulation and improved K /Na ratio when GB03-inoculated plants were grown under elevated salt conditions. This study provides insight for the application of selected bacteria to monocot crops to combat saline toxicity.

In Australia, root-lesion nematode (RLN; Pratylenchus thornei) significantly reduces chickpea and wheat yields. Yield losses from RLN have been determined through use of nematicide; however, nematicide does not control nematodes in Vertosol subsoils in Australia’s northern grains region. The alternative strategy of assessing yield response, by using crop rotation with resistant and susceptible crops to manipulate nematode populations, is poorly documented for chickpea. Our research tested the effectiveness of crop rotation and nematicide against P. thornei populations for assessing yield loss in chickpea. First-year field plots included canola, linseed, canaryseed, wheat and a fallow treatment, all with and without the nematicide aldicarb. The following year, aldicarb was reapplied and plots were re-cropped with four chickpea cultivars and one intolerant wheat cultivar. Highest P. thornei populations were after wheat, at 0.45–0.6 m soil depth. Aldicarb was effective to just 0.3 m for wheat and 0.45 m for other crops, and increased subsequent crop grain yield by only 6%. Canola, linseed and fallow treatments reduced P. thornei populations, but low mycorrhizal spore levels in the soil after canola and fallow treatments were associated with low chickpea yield. Canaryseed kept P. thornei populations low throughout the soil profile and maintained mycorrhizal spore densities, resulting in grain yield increases of up to 25% for chickpea cultivars and 55% for wheat when pre-cropped with canaryseed compared with wheat. Tolerance indices for chickpeas based on yield differences after paired wheat and canaryseed plots ranged from 80% for cv. Tyson to 95% for cv. Lasseter and this strategy is recommended for future use in assessing tolerance.

Chickpea (Cicer arietinum L.) is considered an effective rotation crop in Australia’s northern grains region; however, concerns exist that grain yields of commercial crops are reduced because of nitrogen (N) deficiency related to inadequate nodulation and N₂ fixation. As part of a program to address these issues, we report on the monitoring of 22 commercial fields around Moree, northern NSW, during 2005–07 that were designated for chickpea, and an associated farmer survey (81 respondents). Our objectives were to determine whether the monitored crops were limited by N and to develop recommendations that would optimise productivity for farmers growing chickpeas. In 2005, only soil water and nitrate data were collected from the six fields designated for chickpea. In 2006 and 2007, almost complete datasets were assembled from the 16 chickpea fields or crops, including soil water and nitrate at sowing, row spacing, plant density, plant height, stubble cover, weed density and composition, shoot biomass, grain yield, nodulation and N₂ fixation (%N derived from the atmosphere (%Ndfa) and total crop N fixed). The associated survey provided insights into farmer knowledge of, and practices related to, inoculation.

Field monitoring indicated moderate–high levels of soil nitrate at sowing (averages 114, 126 and 110 kg N ha^–1 to 1.2 m depth for 2005, 2006 and 2007, respectively) and generally low plant nodulation (0.11–1.16 g fresh wt plant^–1) and N₂ fixation (0–62%Ndfa and 0–87 kg N ha^–1). Grain yield varied between 0.53 and 2.91 t ha^–1 across the 14 monitored crops, with averages of 1.89 t ha^–1 in 2006 and 1.02 t ha^–1 in 2007. Although total crop N and grain yields were highly correlated with total (i.e. soil   fixed) N supply, there was no evidence that the monitored chickpea crops were N-limited. Rather, we conclude that soil N and biologically fixed N were complementary in supplying N to the crops, the grain yields of which were primarily determined by the supply of plant-available water (PAW) and water-use efficiency (WUE). Simple and multivariate regression analyses showed that stubble cover during the fallow (positively correlated with sowing PAW) and sowing date (positively correlated with crop WUE) were significant determinants of grain yield. We conclude that farmers could improve inoculation practice by ensuring the time between seed inoculation and sowing is always <24 h.

The agronomic performance of Camelina sativa (L.) Crantz (camelina or false flax) sown in autumn and spring over two consecutive years was tested in northern Italy. Seven C. sativa genotypes were tested and compared with rapeseed (Brassica napus L.). The main phenological stages and biometric traits were recorded, along with seed yield. In general, camelina showed a seed yield similar to that of rapeseed cultivated in the same locality and in the last decade in Italy. On average, the grain yields of camelina and rapeseed grown in the same location and conditions were ∼1340 and 1625 kg ha^–1, respectively. The agronomic performance of camelina varied, with climatic events having a greater effect than sowing season or genotypes. Among the investigated genotypes, however, C. sativa accession CAM 40 was the most adaptable to unfavourable environmental conditions and CAM 172 to favourable conditions. With regard to the two sowing seasons, autumn planting allowed for better performance than spring planting during the second cultivation year. The phenotypic plasticity of camelina was estimated for the first time in the present work. Branching capability was the most plastic trait under favourable yielding conditions. Among the tested genotypes, CAM 40 showed limited yield plasticity and CAM 172 demonstrated high plasticity for the same trait, offering a greater potential for future genetic improvement.

Extraction and fractionation of the culm plus leaves of Chrysopogon serrulatus Trin. produce three major compounds, dibutyl phthalate (DBP), diphenylamine, 4,4′-dioctyl and simiarenol, which potentially act as allelochemicals or phytotoxic compounds. The effects of these compounds were examined using Leptochloa chinensis (L.) Nees as the bioassay species. The isolated compounds showed different degrees of inhibitory effects against L. chinensis. Of the three, DBP was the most potent and was able to inhibit L. chinensis germination by >70% at 500 mg L^–1, followed by simiarenol and diphenylamine, 4,4′-dioctyl with inhibition values ranging from 40 to 52%. Under aerobic conditions, DBP at 2.4 kg a.i. ha^–1 reduced the emergence and shoot fresh weight of L. chinensis by >50%, with negligible effect on root and shoot growth of aerobic rice seedlings, suggesting this as the most suitable rate and compound to control L. chinensis without injuring rice seedlings. At an application on the day of sowing rice seed, across DBP rates, reduction in root and shoot height of rice plants was evident when assessed 14 days after DBP treatment. However, rice plants become less susceptible with increasing growth stage. The findings suggest that DBP has potential to be developed as a pre-emergence, soil-applied natural herbicide for control of L. chinensis in aerobic rice system.

Seed dormancy could be a factor related to natural reseeding of hairy vetch (Vicia villosa ssp. villosa Roth.), a winter annual species cultivated for seed, pasture, hay, green manure and cover crop. The presence of combinational dormancy (physical dormancy   physiological dormancy, PY   PD) in hairy vetch was explored by a model using laboratory and field measures. At the stage of natural dispersal, dry seeds of hairy vetch were stored under laboratory conditions at 5, 10, 20 and 30°C (±2°C) or buried at 5 cm depth in an experimental field. Germination at 5, 8, 10, 15, 20 and 25°C was assessed at regular intervals up to 295 days after harvest. Following the hypothesis of the existence of a combinational dormancy mechanism, model development was based on the estimation of: (i) the fraction of non-PY seed as a function of after-ripening thermal-time accumulation, and (ii) seed population thermal parameters associated with a given level of PD. The developed model adequately described the after-ripening thermal-time requirements for PY   PD release of V. villosa. Based on model predictions, under a semi-arid thermal regime, >45% of vetch seeds shed during the summer season would be able to germinate during early autumn. Thus, the seed-bank size threshold at the end of the first growing season should be >65 seeds m^–2 in order to reach a minimum stand of 30 plants m^–2 necessary for a productive pasture.

This study characterised 16 tropical perennial grass species in terms of in vitro methane output and related their digestibility and rumen fermentation with methane output. The grass samples were collected, dried in a forced oven, and ground and analysed for nutrient composition. In vitro gas production and organic matter digestibility (IVOMD) were determined using rumen fluid collected, strained and anaerobically prepared. A semi-automated system was used to measure gas production through in vitro incubation at 39°C. Anthephora argentea and Stipagrostis ciliate produced the highest concentration of methane in terms of g kg^–1 digestible dry matter (DDM) and g kg^–1 digestible organic matter (IVOMD). Cenchrus ciliaris, Setaria verticillata and Panicum coloratum produced the lowest (P < 0.05) methane when expressed in terms of g kg^–1 DDM and g kg^–1 IVOMD. Ash, ether extract, non-fibrous carbohydrate, neutral and acid detergent insoluble nitrogen, and crude protein were negatively correlated with methane production. Methane production positively correlated with neutral and acid detergent fibre, cellulose and hemicellulose. It is important to focus on screening and selecting perennial grass with higher nitrogen content and low methane production to mitigate methane production under tropical conditions.