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Wheat is critical for food security, and is challenged by biotic stresses, chiefly aphids and the viruses they transmit. The objective of this study was to determine whether aphids feeding on wheat could trigger a defensive plant reaction to oxidative stress that involved plant oxylipins. Plants were grown in chambers with a factorial combination of two nitrogen rates (100% N vs. 20% N in Hoagland solution), and two concentrations of CO2 (400 vs. 700 ppm). The seedlings were challenged with Rhopalosiphum padi or Sitobion avenae for 8 h. Wheat leaves produced phytoprostanes (PhytoPs) of the F1 series, and three types of phytofurans (PhytoFs): ent-16(RS)-13-epi-ST-Δ14-9-PhytoF, ent-16(RS)-9-epi-ST-Δ14-10-PhytoF and ent-9(RS)-12-epi-ST-Δ10-13-PhytoF. The oxylipin levels varied with aphids, but not with other experimental sources of variation. Both Rhopalosiphum padi and Sitobion avenae reduced the concentrations of ent-16(RS)-13-epi-ST-Δ14-9-PhytoF and ent-16(RS)-9-epi-ST-Δ14-10-PhytoF in relation to controls, but had little or no effect on PhytoPs. Our results are consistent with aphids affecting the levels of PUFAs (oxylipin precursors), which decreased the levels of PhytoFs in wheat leaves. Therefore, PhytoFs could be postulated as an early indicator of aphid hosting for this plant species. This is the first report on the quantification of non-enzymatic PhytoFs and PhytoPs in wheat leaves in response to aphids.

Abstract Protagonists allege that artificial intelligence (AI) is revolutionising contemporaneous mindscapes. Here, we authoritatively review the status quo of AI and machine learning application in irrigated agriculture, evaluating the potential of, and challenges associated with, a wide range of existential AI approaches. We contend that aspiring developers of AI irrigation systems may benefit from human-centred AI, a nascent algorithm that captures diverse end-user views, behaviours and actions, potentially facilitating refinement of proposed systems through iterative stakeholder feedback. AI-guided human–machine collaboration can streamline integration of user needs, allowing customisation towards situational farm management adaptation. Presentation of big data in intuitive, legible and actionable forms for specialists and laypeople also urgently requires attention: here, AI-explainable interpretability may help harness human expertise, enabling end-users to contribute their experience within an AI pipeline for bespoke outputs. Transfer learning holds promise in contextualising place-based AI to agroecological regions, production systems or enterprise mixes, even with limited data inputs. We find that the rate of AI scientific and software development in recent times has outpaced the evolution of adequate legal and institutional regulations, and often social, moral and ethical license to operate, revealing consumer issues associated with data ownership, legitimacy and trust. We opine that AI has great potential to elicit sustainable outcomes in food security, social innovation and environmental stewardship, albeit such potential is more likely to be realised through concurrent development of appropriate ethical, moral and legal dimensions.

Abstract Interactions between plants and herbivores are key drivers of evolution and ecosystem complexity. We investigated the role of plant labile carbohydrates and nitrogen on wheat-aphid relations in a 22 factorial combining [CO2] and nitrogen supply. We measured life history traits (assay 1) and feeding behaviour (assay 2) of bird-cherry oat aphid (Rhopalosiphum padi L.) and English grain aphid (Sitobion avenae F.) forced to feed on single leaf laminae, and reproduction of R. padi in a setting where insects moved freely along the plant (assay 3). Experimental setting impacted aphid traits. Where aphids were constrained to single leaf, high nitrogen reduced their fitness and discouraged phloem feeding. Where aphids could move throughout the plant, high nitrogen enhanced their reproduction. Aphid responses to the interaction between nitrogen and [CO2] varied with experimental setting. The number of R. padi adults varied tenfold with plant growing conditions and correlated negatively with molar concentration of sugars in stem (assay 3). This finding has two implications. First, the common interpretation that high nitrogen favours insect fitness because protein-rich animal bodies have to build from nitrogen-poor plant food needs expanding to account for the conspicuous association between low nitrogen and high concentration of labile carbohydrates in plant, which can cause osmotic stress in aphids. Second, the function of labile carbohydrates buffering grain growth needs expanding to account for the osmotic role of carbohydrates in plant resistance to aphids.

Plastic film mulching often increases the yield of winter wheat in the Loess Plateau of China, but the physiological mechanisms are unclear, especially in response to the interaction between mulch and water supply. In this study, we investigated the interactive effects of initial soil water (dry, moderate, and wet), soil cover (plastic mulch, bare soil), and seasonal conditions on the dynamics of dry matter partitioning, water-soluble carbohydrates (WSC), and flag leaf senescence, and their relations with yield and its components. Plastic mulch increased dry matter accumulation at anthesis and maturity relative to bare soil, with no interaction with season or initial soil water. Allocation of dry matter to leaf, stem, and spike did not change with soil cover. Compared with bare soil, mulch increased WSC accumulation by 14% at anthesis and its translocation by 16%. Soil cover did not influence the senescence of flag leaf after anthesis as indicated by similar dynamics of the C:N ratio. Grain yield was higher under plastic mulch than bare soil in two out of three seasons, and was associated with a higher translocation amount of WSC and post-anthesis dry matter that linked grain weight, grain number, and harvest index.

Aim: To evaluate the effect of elevated temperature on the yield of Shiraz vines in the Barossa Valley of Australia. Methods and results: We compiled and analysed 37 pair-wise yield comparisons between heated and control vines spaning seven consecutive vintages from 2009-10. Heating with open-top chambers increased daily average temperature by approx. 2 °C above ambient in realistic vineyard conditions, in comparison to 0.9 to 2.9 °C projected warming for south-eastern Australia (2030-2070). The combination of seasons, varieties, fruit loads, pruning times, and water regimes returned an 8.5-fold variation in the yield of unheated vines. Warming had no statistically significant effect on yield in 32 out of 37 comparisons, reduced yield in 2 and increased yield in 3. Conclusion: Projected warming is unlikely to cause widespread reduction of yield in environments with thermal regimes similar to Barossa Valley; extrapolation to cooler or warmer regions is not warranted. Significance and impact of the study: The relevance of this finding is three-fold. First, it demonstrates vine resilience against the target of the Paris Agreement setting a long-term goal of holding global warming below 2 °C. Second, further research on adaptation to warming needs to focus on logistic issues such as early harvest, and fruit composition with implications for wine quality, rather than yield. Third, this summary data set is a robust reference to benchmark time-series and modelling analysis of vine yield in response to warming.