In-crop nitrogen (N) application is used widely in rainfed winter wheat production to reduce lodging risk; however, uncertainty exists as to its ability to reduce lodging risk in subtropical irrigated wheat production without simultaneously reducing yield potential. The objective of this study was therefore to determine whether in-crop N application reduces lodging risk without reducing yield of irrigated spring wheat in a subtropical environment. Irrigated small-plot experiments were conducted to compare the effect of alternative N timing on lodging and yield in two cultivars. Variable N regimes were imposed during the vegetative growth phase, after which additional N was applied to ensure that total season N application was uniform across N-timing treatments. Treatments with low N at sowing had significantly less lodging and were the highest yielding, exhibiting yield increases of up to 0.8 t ha^–1 compared to treatments with high N at sowing. Increased leaf area index, biomass and tiller count at the end of the vegetative growth phase were correlated with increased lodging in both cultivars, although the strength of the correlation varied with cultivar and season. We conclude that canopy-management techniques can be used to simultaneously increase yield and decrease lodging in irrigated spring wheat in the subtropics, but require different implementation from techniques used in temperate regions of Australia.

The high-rainfall zone (HRZ) of southern Australia is the arable areas where annual rainfall is between 450 and 800 mm in Western Australia and between 500 and 900 mm in south-eastern Australia, resulting in a growing-season length of 7–10 months. In the last decade, there has been a growing recognition of the potential to increase crop production in the HRZ. We combined (1) a survey of 15 agricultural consultants, each of whom have ∼40–50 farmer clients across the HRZ, (2) 28 farm records of crop yields and area for 2000–2010, (3) 86 wheat and 54 canola yield observations from well managed experiments, and (4) long-term simulated crop yields at 13 HRZ locations, to investigate recent trends in crop production, quantify the gap between potential and actual crop yields, and consider the factors thought to limit on-farm crop yields in the HRZ. We found in the past 10 years a trend towards more cropping, particularly in WA, an increased use of canola, and advances in the adaptation of germplasm to HRZ environments using winter and longer-season spring types. Consultants and the farm survey data confirmed that the rate of future expansion of cropping in the HRZ will slow, especially when compared with the rapid changes seen in the 1990s.

In Victoria, New South Wales and South Australia the long-term water-limited potential yield in HRZ areas, as measured by experimental yields, consultant estimates and simulations for slow developing spring cultivars of wheat and canola was 5–6 and 2–3 t/ha for a decile 5 season. For Western Australia it was 4–5 and 2–3 t/ha, where yields were less responsive to good seasons than in the other states. The top performing farmers were achieving close to the water-limited potential yield. There are yield advantages of ∼2 t/ha for ‘winter’ over ‘spring’ types of both wheat and canola, and there is scope for better adapted germplasm to further raise potential yield in the HRZ.

Consultants stated that there is scope for large gains in yield and productivity by encouraging the below-average cropping farmers to adopt the practices and behaviours of the above-average farmers. The scope for improvement between the below- and above-average farmers was 1–3 t/ha for wheat and 0.5–1.5 t/ha for canola in a decile 5 season. They also stated that a lack of up-to-date infrastructure (e.g. farm grain storage) and services is constraining the industry’s ability to adopt new technology. Priorities for future research, development and extension among consultants included: overcoming yield constraints where growing-season rainfall exceeds 350 mm; adaptation of winter and long-season spring types of cereals and canola and management of inputs required to express their superior yield potential; and overcoming barriers to improved planning and timeliness for crop operations and adoption of technology.

Low-molecular-weight glutenin subunits (LMW-GS) are a component of the gluten network and play a key role in determining the viscoelastic properties of wheat dough. Aegilops species have been shown to be an important source of variation for valuable traits for wheat breeding. However, very little is known about LMW-GS genes in section Sitopsis species, which are closely related to the B genome of common wheat. Ten accessions of Sitopsis species were evaluated for variability of LMW-GS genes, and 20 novel genes were obtained, of which nine were LMW-m and 11 were LMW-s genes. Only two were pseudogenes, corresponding to one LMW-m and one LMW-s gene. Six groups of genes were detected: three for each of the LMW-m and LMW-s genes. All groups of LMW-s genes and one of LMW-m genes (pGluU) detected were not related to B-genome genes from common wheat, whereas the remaining genes were. The single-nucleotide polymorphisms, and insertions and deletions, detected in active variants compared with those from common wheat could affect structure protein. The analysis of reactive epitopes for coeliac disease revealed that LMW-s subunits lacked toxicity, as did the pGluU LMW-m subunits; the other LMW-m subunits were less toxic than that from common wheat.

Pearl millet (Pennisetum glaucum (L.) R.Br.) is widely grown in some of the driest regions of the world, mainly drier tropics. Although it is easy to cultivate under semi-arid and arid regions, it still responds very favourably to slight improvements in growing conditions such as supplementary irrigation. Because this crop is mostly cultivated under water-limited conditions, there is a need to develop strategies to promote efficient water use, and this can be achieved through field experiments and or crop modelling. The AquaCrop model requires a minimum number of crop parameters, with the aim of balancing simplicity, accuracy, robustness and user-friendliness. In this study, we calibrate and validate the AquaCrop model for an underutilised crop, pearl millet under irrigation and rainfed conditions. Experiments were carried out in lysimeters with two varieties of pearl millet (GCI 17, improved variety; Monyaloti, local variety) during the 2010–11 season. Field trials were conducted during the 2008–09 and 2009–10 seasons. The field plot was under a line-source sprinkler with four replications. Lysimeter datasets and field data (2008–09) were used for parameterisation and calibration of the model, and validation was done with the 2009–10 dataset. The model was able to simulate canopy cover, biomass production, cumulative evapotranspiration and grain yield, but not soil-water content, for the two varieties of pearl millet under irrigation and rainfed conditions. The performance of the model in simulating soil-water content is moderate for this crop and needs to be improved.

The projected increase in mean temperatures caused by climate change is expected to have detrimental impacts on berry quality. Microorganisms as arbuscular mycorrhizal fungi (AMF) produce numerous benefits to host plants and can help plants to cope with abiotic stresses such as high temperature. The aims of this research were to characterise the response of three clones of Vitis vinifera L. cv. Tempranillo to elevated temperatures and to determine whether AMF inoculation can improve berry antioxidant properties under these conditions. The study was carried out on three fruit-bearing cuttings clones of cv. Tempranillo (CL-260, CL-1048 and CL-1089) inoculated with AMF or uninoculated and subjected to two temperature regimes (day–night: 24°C−14°C and 28°C−18°C) during berry ripening. Results showed that clonal diversity of Tempranillo resulted in different abilities to respond to elevated temperature and AMF inoculation. In CL-1048, AMF inoculation improved parameters related to phenolic maturity such as anthocyanin content and increased antioxidant activity under elevated temperature, demonstrating a protective role of AMF inoculation against warming effects on berry quality. The results therefore suggest that selection of new clones and/or the implementation of measures to promote the association of grapevines with AMF could be strategies to improve berry antioxidant properties under future warming conditions.

Amphicarpy is an adaptation that enhances persistence under various environmental stresses, including heavy grazing, through the production of both aerial and underground seeds on the same plant. The trait occurs in several Australian endemic tropical herbaceous legumes, including Vigna lanceolata. The objective of the current research was to compare aerial and underground reproductive structures in six amphicarpic morphotypes of V. lanceolata (four perennials and two annuals), and in hybrids among these morphotypes and also with a seventh, non-amphicarpic perennial morphotype. The aim was to establish how easily the trait might be manipulated in a breeding program to develop improved amphicarpic cultivars, for ley and forage purposes. In the four amphicarpic perennials, the underground fruiting structures formed on leafless underground stems or rhizomes, and in all four, amphicarpy was habitual, i.e. individual plants routinely developed both aerial and underground fruiting structures. In the two annuals, the underground fruiting structures developed on specialised axillary geotropic stems that arose along the prostrate aerial stems and penetrated the soil or leaf litter. One of the annuals exhibited habitual amphicarpy, whereas the other was opportunistic, in that the underground fruiting structures developed only where aerial stems became covered with soil or leaf litter. F₁ hybrids between the two annual morphotypes exhibited habitual amphicarpy, indicating dominance of habitual over opportunistic amphicarpy. F₁ hybrids between the four perennial amphicarpic morphotypes were all amphicarpic, reflecting the similar expression of the trait in these forms. By contrast, when these four were crossed with the non-amphicarpic perennial, none of the viable F₁ hybrids exhibited amphicarpy, suggesting dominance for non-expression. Many of the perennial F₁ hybrids were self-sterile, but in the hybrids that were at least partially fertile, many more geocarpic than aerial seeds were produced, raising the possibility that in the wild, amphicarpy may facilitate the persistence of chance natural outcrosses that might otherwise not survive. The results suggested that it would be feasible to develop amphicarpic annual and amphicarpic perennial cultivars for, respectively, ley and forage purposes.

Stem lodging causes significant losses in crops of cereals and oilseeds. The aim of the present study was to identify the anatomical causes that generate differences in response to stem lodging in sunflower. Two sunflower hybrids (Stay-Green, resistant to stem lodging; Zenit, susceptible to stem lodging) were grown at three crop population densities and artificially lodged at two advanced ontogeny stages (R7 and R8), which were preceded by ethephon application near the flower button stage (R1). Measurements included stem failure moment of force (Bs), thickness of primary and secondary structures in the stem lodging zone (t), diameter of the stem lodging zone (di), sclerenchyma packages area (sp), secondary xylem tissue area (xt) and yield. Stay-Green had significantly higher values for Bs, t, di, sp and xt. At higher crop densities and more advanced ontogeny stages these parameters were reduced, favouring stem lodging, although the effects were ameliorated by ethephon application through anatomical modifications. Zenit exhibited the greatest responses to ethephon application. The present study is the first field study identifying anatomical changes causing stem lodging and intraspecific variability in sunflowers. The information provided can be used by geneticists in selection programs for stem lodging tolerance in the context of increasing crop population densities to improve sunflower yield.

With the view to extending the cultivation of common buckwheat to Mediterranean environments, we investigated the responses of two varieties to three sowing times, early spring, late spring and late summer, in rainfed and irrigated conditions. Plants were harvested at two ripening stages for forage production and at maturity for grain yield. The crop cycle lasted 82–88 days independent of sowing time, whereas the thermal time was ∼1000 degree-days in early spring and late summer sowings, and 1200 degree-days when sown in late spring. Forage yield increased up to 75% between ripening stages. Early spring was the best sowing time for forage (4 t ha^–1 dry weight) and grain yield (2 t ha^–1 dry weight) in rainfed conditions. Late spring sowings give the highest forage yield when irrigated (6 t ha^–1 dry weight), but were not suitable for producing grain, for the adverse effect of high summer temperatures on seed set and seed filling. Late summer sowings produced acceptable grain yield (1.5 t ha^–1 dry weight), whereas short days and low temperatures limited forage production. Thus, in Mediterranean environments, buckwheat could be profitably introduced as a minor summer crop, sown in early spring for grain production and in late spring for forage production.

The resistance of a diverse range of Trifolium species (clovers) to a highly virulent bluegreen aphid (BGA, Acyrthosiphon kondoi Shinji) population (Urrbrae 2011) collected in South Australia was assessed in greenhouse and field experiments, with the aims of determining the potential impact of this insect pest on biomass and identifying resistant genotypes for future plant-breeding activities. Resistance to BGA was found in populations of clovers that show some level of outcrossing—white clover (T. repens L.), rose clover (T. hirtum All.), crimson clover (T. incarnatum L.) and red clover (T. pratense L.)—and in one entry of the inbreeding subspecies of subterranean clover, T. subterraneum L. subsp. subterraneum (Katzn. and Morley). Resistance was not found in T. s. brachycalycinum (Katzn. and Morley) or T. s. yanninicum (Katzn. and Morley). In a greenhouse experiment, damage from BGA resulted in forage yield penalties of 72–100% when aphids were inoculated at 14 days after sowing and 13−74% when inoculated at 42 days after sowing, showing that in optimum conditions BGA can be a serious pest of clovers. Observations of severe damage caused by BGA in two regenerating field trials in southern New South Wales confirmed that field damage could occur in seasons favourable to aphid growth and reproduction. The severe damage that BGA can cause to clovers, and the sources of resistance we found, suggest that breeding for BGA resistance in clovers is warranted and feasible.