Mungbean (Vigna radiata L. Wilczek var. radiata) is an important food crop cultivated on over 6 Mha throughout the world. Its short duration of 55–70 days, capacity to fix atmospheric nitrogen, and exceptional grain nutritional profile makes the crop a staple for smallholder and subsistence farmers. In Australia, mungbean is grown as a high-value export crop and established as a main summer rotation for dryland farmers. A major threat to the integrity of the industry is halo blight, a bacterial disease leading to necrotic lesions surrounded by a chlorotic halo that stunts and ultimately kills the plant. Caused by Pseudomonas savastanoi pv. phaseolicola, this seed-borne disease is extremely difficult to control, resulting in significant yield loss and production volatility. The challenge of managing halo blight is exacerbated by a wide host range that includes many legume and weed species, and the presence of multiple epidemiologically significant strains. Molecular technologies could play a pivotal role in addressing these issues. This review synthesises current and emerging technologies to develop improved management strategies for the control of halo blight in mungbean.

K-Type cytoplasmic male sterility (K-CMS) plays an important role in breeding hybrid wheat. This study was designed to investigate the association of sucrose metabolism with K-CMS in wheat (Triticum aestivum L.) anthers at the binucleate stage. Levels of sucrose in the anthers of the K-CMS line remained higher than in the fertile line, but glucose and fructose contents in the anthers of the K-CMS line were dramatically lower than in the fertile line. Compared with the fertile line, the activities of cell-wall-bound invertase (CWIN), neutral invertase and vacuolar invertase (VIN) were significantly reduced. Quantitative real-time polymerase chain reaction analyses showed that the expression levels of one CWIN gene (IVR1), one VIN gene (IVR5) and a sucrose transporter gene (TaSUT1) were significantly downregulated in K-CMS anthers. Furthermore, western blot confirmed that the protein expression level of IVR1 was higher in sterile anthers than in male fertile anthers. Thus, it appears that the accumulation of sucrose in K-CMS anthers might involve a decrease in activity and a reduction in content of invertase. In conclusion, the results suggest that an inability to metabolise incoming sucrose to hexoses may be involved in the K-CMS pollen-developmental lesion.

Herbicide-resistant weeds have prompted the development of non-chemical weed-control techniques for sustainable crop production. We examined the potential of pre-emergence microwave (MW) soil treatment to suppress weeds and enhance grain yield in rice (Oryza sativa L.) cropping in two agro-ecological zones of Australia. An experimental MW weed killer, which has four, independently controlled, 2-kW MW generators operating at 2.45 GHz, was used to treat the soil before cropping under field conditions. A once-off MW soil treatment (duration 60 s) and an untreated control were assigned in a randomised complete block design with five replicates at two study locations: Dookie (Victoria) and Jerilderie (New South Wales). Simpson’s numerical surface integral approximation estimated the applied energy density of ∼500 J cm^–2. This energy increased the soil’s temperature up to 70–75°C in top soil horizon (0–6 cm) as depicted by infrared thermal imaging. No statistically significant difference was detected for weed control between MW and untreated control plots at either study location. At Dookie, grain yield did not significantly increase in response to MW soil treatment, whereas at Jerilderie, grain yield was 20% higher (P < 0.05) with MW soil treatment than in control plots. At Jerilderie, the irrigation water use efficiency (t ML^–1) was 21% higher in MW plots than control plots. In summary, MW exposure of 60 s appeared to be an insufficient heating duration for seedbank depletion. This suggests further treatment modification followed by rigorous testing under different soils conditions using the MW prototype.

Barley (Hordeum vulgare L.) is cultivated globally under a wide range of climatic conditions and is subjected to chilling and freezing stresses under temperate and cold climatic conditions. As a mycorrhizal crop, barley may benefit from this association for increasing cold resistance. In order to investigate the effects of inoculation with arbuscular mycorrhizal fungi (AMF) on cold-stress resistance in barley plants, one winter and one spring cultivar were grown under control (25°C day, 17°C night) and low, non-freezing (LT: 5°C day, 3°C night) temperatures for 3 weeks in the absence (−AMF) or presence (+AMF) of two species of AMF, Glomus versiforme and Rhizophagus irregularis. In addition, the influence of LT (as an acclimation treatment) was studied on plant survival after a 2-day exposure to freezing temperature (FT: −5°C in dark). Biomass production, membrane integrity and survival rate of plants indicated that the winter cultivar was more tolerant than the spring cultivar. Inoculation with AMF resulted in improved growth, photosynthesis, osmotic and water homeostasis, and potassium uptake under both control and LT conditions, whereas the effect on membrane integrity, antioxidative defence and phenolics metabolism was mainly observed in LT plants. AMF inoculation substituted partially or completely for acclimation treatment and increased the survival rate of FT plants, with the highest survival achieved in a combination of AMF and LT. Mycorrhizal responsiveness was higher in LT plants. Despite the lower AMF colonisation, G. versiforme was often more effective than R. irregularis for the alleviation of low temperature stress in both cultivars, whereas R. irregularis was more effective in increasing the survival rate. Our data suggest that the right combination of fungus species and host-plant cultivar is important for successful utilisation of AMF under cold conditions.

Intercropping is commonly practiced worldwide because of its benefits to plant productivity and resource-use efficiency. Belowground interactions in these species-diverse agro-ecosystems can greatly contribute to enhancing crop yields; however, our understanding remains quite limited of how plant roots might interact to influence crop biomass, photosynthetic rates, and the regulation of different proteins involved in CO₂ fixation and photosynthesis. We address this research gap by using a pot experiment that included three root-barrier treatments with full, partial and no root interactions between foxtail millet (Setaria italica (L.) P.Beauv.) and peanut (Arachis hypogaea L.) across two growing seasons. Biomass of millet and peanut plants in the treatment with full root interaction was 3.4 and 3.0 times higher, respectively, than in the treatment with no root interaction. Net photosynthetic rates also significantly increased by 112–127% and 275–306% in millet and peanut, respectively, with full root interaction compared with no root interaction. Root interactions (without barriers) contributed to the upregulation of key proteins in millet plants (i.e. ribulose 1,5-biphosphate carboxylase; chloroplast β-carbonic anhydrase; phosphoglucomutase, cytoplasmic 2; and phosphoenolpyruvate carboxylase) and in peanut plants (i.e. ribulose 1,5-biphosphate carboxylase; glyceraldehyde-3-phosphate dehydrogenase; and phosphoglycerate kinase). Our results provide experimental evidence of a molecular basis that interspecific facilitation driven by positive root interactions can contribute to enhancing plant productivity and photosynthesis.

Stimulation of grain yield under elevated [CO₂] grown plants is often associated with the deterioration of grain quality. This effect may be further complicated by the frequent occurrence of drought, as predicted in most of the climate change scenarios. Lentil (Lens culinaris Medik.) and faba bean (Vicia faba L.) were grown in the Australian Grains Free Air CO₂ Enrichment facility under either ambient CO₂ concentration ([CO₂], ∼400 µmol mol^–1) or elevated [CO₂] (e[CO₂], ∼550 µmol mol^–1), and with two contrasting watering regimes (for faba bean) or over two consecutive seasons contrasting in rainfall (for lentil), to investigate the interactive effect of e[CO₂] and drought on concentrations of selected grain minerals (Fe, Zn, Ca, Mg, P, K, S, Cu, Mn, Na). Grain mineral concentration (Fe, Zn, Ca, K, S, Cu) increased and grain mineral yield (i.e. g mineral per plot surface area) decreased in dry growing environments, and vice versa in wet growing environments. Elevated [CO₂] decreased Fe, Zn, P and S concentrations in both crops; however, the relative decrease was greater under dry (20–25%) than wet (4–10%) growing conditions. Principal component analysis showed that greater grain yield stimulation under e[CO₂] was associated with a reduction in Fe and Zn concentrations, indicating a yield dilution effect, but this was not consistently observed for other minerals. Even if energy intake is kept constant to adjust for lower yields, decreased legume micronutrients densities under e[CO₂] may have negative consequences for human nutrition, especially under drier conditions and in areas with less access to food.

Although many interspecific crosses in Cicer species have successfully been carried out to improve the population in cultivated chickpea (Cicer arietinum L.), interspecific and backcross populations derived from mutants of Cicer species have not been studied for revealing suppressed genes responsible for heterotic effects and transgressive segregations. Therefore, the study aimed (i) to estimate heterosis (here, offspring superior to mid-parent value) and heterobeltiosis (offspring superior to better parent) for yield and yield components in the F₁; (ii) to decipher transgressive segregation (extreme phenotypes) in F₂ and backcross populations; and (iii) to reveal suppressed genes in interspecific and backcross populations (C. arietinum × F₁ and C. reticulatum Ladiz.× F₁) derived from interspecific crosses between a mutant of C. arietinum and a mutant of C. reticulatum. Heterobeltiosis was found for seed and biological yields, number of branches, and number of pods per plant in F₁ progeny; heterosis was determined for the additional traits of 100-seed weight and harvest index. Heterobeltiosis and heterosis for yield and yield components in F₁ progeny prompted transgressive segregation for these traits in F₂ and backcross populations. In the backcrosses, C. arietinum × F₁ crosses produced greater seed size and more pods per plant than C. reticulatum × F₁, suggesting that C. arietinum × F₁ backcrossing could improve yield components and lead to large seed size. Most of the high-yielding progeny in F₂ and C. arietinum × F₁ populations had double-podded nodes. It was concluded that the suppressed genes in a mutant of C. reticulatum or a mutant of C. arietinum played a crucial role in increasing transgressive segregations and allowing the cultivated chickpea to gain increased yield and yield components as well as large seed size.

The annual forage legume biserrula (Biserrula pelecinus L.) offers a promising opportunity as a low-methanogenic, bioactive pasture for southern Australian grazing systems where subterranean clover (Trifolium subterraneum L.) is the dominant annual pasture legume. This in vitro study to assess methanogenic potential examined how growth stage and cutting of biserrula affect biomass, nutritive value and fermentative parameters including methanogenic potential compared with subterranean clover. Both species were grown in a glasshouse, where three growth-stage treatments comprised plant collection at vegetative, reproductive or maturity growth stages. Three cutting (simulated grazing) treatments included cutting at the vegetative or reproductive stage and an uncut control, with herbage collection at maturity. Methane production in biserrula was unaffected by the stage of growth. Other nutritive value and fermentative parameters varied significantly with growth stage, the highest fibre content and lowest crude protein (CP) being found at maturity. Regrowth from herbage cut at the reproductive stage had higher CP and lower biomass than other cut treatments. In biserrula, this regrowth also showed the highest fermentability of the three cutting treatments including elevated methane yield. Notwithstanding these treatment effects on fermentability, biserrula maintained its strong anti-methanogenic advantage over subterranean clover across all treatments, confirming its potential as an anti-methanogenic bioactive pasture.

Medicago plants such as M. sativa (lucerne, alfalfa) are important forage all over the world. Freezing-tolerance capacity is one of the key determinants of the survival and production of Medicago. In order to explore the molecular basis underlying freezing tolerance, we sequenced the root transcriptomes of five Medicago varieties belonging to two species, M. sativa and M. varia, and compared their gene expression and molecular evolution. A range of 19.5–23.8 Gb clean bases was obtained, and de novo transcriptome assembly generated 205 238–268 520 unigenes. The GO (Gene Ontology) terms of basic biological processes such as binding, cell and metabolism were most represented for the unigenes. In addition, a large number of unigenes related to GO terms and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways of membrane, signalling, transcription and response to stimulus were identified in functional annotation. In total, 12 455 orthologs were identified among the five Medicago varieties. Among the orthologs, many unigenes that directly related to freezing tolerance were highly expressed in all five varieties, including genes for WRKY transcription factors, calcium-binding factors, and antioxidant enzymes such as catalase and ascorbate peroxidase. Molecular evolution testing showed that the unigenes involved in membrane shared high K_a/K_s (non-synonymous/synonymous substitution rate) across all the five Medicago varieties. Positively selected genes were mainly involved in transcription regulation, metabolism and signal transduction. Our study provides a large transcriptome dataset in the Medicago genus and brings new insights into the freezing tolerance for Medicago species.

Charles Sturt University has operated a commercial herbicide resistance testing service since 1991, following a random survey of the South West Slopes region of New South Wales that identified significant incidence of herbicide resistance in annual ryegrass (Lolium rigidum Gaud.). Other surveys of cropping regions of southern Australia conducted at that time also found a significant incidence of resistance. In the subsequent 25-year period, the testing service has received samples from the majority of the southern Australian cropping belt. Overall, 80% of samples tested were resistant to acetyl-CoA carboxylase (ACCase) inhibiting aryloxyphenoxypropionate and phenylpyrazole herbicides, 56% to acetolactate synthase (ALS) inhibiting herbicides, and 24% to ACCase-inhibiting cyclohexanedione herbicides. The incidences of resistance to inhibitors of photosynthesis at PSII, tubulin-formation inhibitors, and 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase inhibiting herbicides have remained <10% of samples tested. The relationships between many herbicide groups and subgroups are discussed, as is the variability in resistance incidence and the forms of cross or multiple resistance for each state. This paper builds on an earlier publication of 14 years of testing history. At >5000 samples, the size and geographical spread of this dataset allows for valuable analyses of the relationships present in herbicide-resistant populations of annual ryegrass.