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Technologies, from molecular genetics to precision agriculture, are outpacing theory, which is becoming a bottleneck for crop improvement. Here, we outline theoretical insights on the wheat phenotype from the perspective of three evolutionary and ecologically important relations—mother–offspring, plant–insect and plant–plant. The correlation between yield and grain number has been misinterpreted as cause-and-effect; an evolutionary perspective shows a striking similarity between crop and fishes. Both respond to environmental variation through offspring number; seed and egg size are conserved. The offspring of annual plants and semelparous fishes, lacking parental care, are subject to mother–offspring conflict and stabilizing selection. Labile reserve carbohydrates do not fit the current model of wheat yield; they can stabilize grain size, but involve trade-offs with root growth and grain number, and are at best neutral for yield. Shifting the focus from the carbon balance to an ecological role, we suggest that labile carbohydrates may disrupt aphid osmoregulation, and thus contribute to wheat agronomic adaptation. The tight association between high yield and low competitive ability justifies the view of crop yield as a population attribute whereby the behaviour of the plant becomes subordinated within that of the population, with implications for genotyping, phenotyping and plant breeding. [ABSTRACT FROM AUTHOR]

The evolution in the definition of crop yield—from the ratio of seed harvested to seed sown to the contemporary measure of mass of seed per unit land area―has favoured less competitive phenotypes. Here we use binary mixtures of cultivars spanning five decades of selection for yield and agronomic adaptation to ask three questions. First, what is the degree of symmetry in the response of yield to neighbour; this is, if an older, more competitive cultivar increases yield by 10% with a less competitive neighbour in comparison to pure stands, would the newer, less competitive cultivar reduce yield by 10% when grown with older neighbour. Lack of symmetry would indicate factors other than competitive ability underly yield improvement. Second, what are the yield components underlying competitive interactions. Third, to what extent are the responses to neighbour mediated by radiation, water and nitrogen. A focus on yield components and resources can help the interpretation of shifts in the crop phenotype in response to selection for yield. The rate of genetic gain in yield over five decades was 24 kg ha−1 year−1 or 0.61% year−1. A strongly symmetrical yield response to neighbour indicates that yield improvement closely associates with a reduction in competitive ability. Response to neighbour was larger for grain number and biomass than for grain weight and allocation of biomass to grain. Under our experimental conditions, competition for radiation was dominant compared to competition of water and nitrogen. High‐yielding phenotypes had lower competitive ability for radiation but compensated with higher radiation use efficiency, a measure of canopy photosynthetic efficiency. Genetic and agronomic manipulation of the crop phenotype to reduce competitive ability could further improve wheat yield to meet the challenge of global food security. [ABSTRACT FROM AUTHOR]

Wheat, rice, and maize collectively provide the bulk of energy and protein to the human diet worldwide. Over the last seven decades, China increased 5.8-fold the aggregated production of the three cereals, but further gains are required to meet the predicted demand of 776 Mt. by 2030. Here, we report the rate of genetic gain in yield of 0.65% year-1 for wheat between 1937 and 2012, 0.69% year-1 for rice between 1934 and 2011, and 0.77% year-1 for maize between 1950 and 2014 in China. National farm yield in the same periods increased 1.38% year-1 for wheat, 1.15% year-1 for rice and 1.32% year-1 for maize. Hence, genetic improvement (G) accounted for 47%-60% of the increase in farm yield, with improved management (M) and G × M interaction accounting for the balance. The absolute rate of genetic gain (kg ha-1 year-1) was proportional to environmental potential. Genetic gain in nitrogen utilization efficiency (yield per unit nitrogen uptake) was significant for all three crops and was achieved at the expense in grain N concentration that decreased at 0.19% year-1 in rice and 0.47% year-1 in maize. To guarantee future food security and environmental sustainability, breeding and agronomic efforts need to increase the rate of gain in yield and revert the declining trends in grain protein by improving nitrogen uptake and nitrogen harvest index. [ABSTRACT FROM AUTHOR]

Highlights • Genetic gains of Australian wheat were associated with higher water-nitrogen co-limitation. • Higher water-nitrogen co-limitation associated with a higher nitrogen uptake per unit of evapotranspiration. • Nitrogen traits are critical for drought adaptation. Abstract The interactions between nitrogen (N) and water are manifold, and the concept of co-limitation provides a quantitative framework for integration. This paper tested the hypothesis that selection for yield increased water-N co-limitation in wheat adapted to winter rainfall environments of Australia. To test this hypothesis, we measured evapotranspiration, N uptake and yield in a historic collection of varieties released between 1958 and 2007 (exp. 1) and between 1969 and 2015 (exp. 2). Crops were grown under 5 (exp. 1) or 4 (exp. 2) environmental conditions resulting from the combination of sites, seasons, and supply of N and water. Genetic gain of yield, i.e. the slope of the regression between yield and year of release was 14–24 kg ha−1 y−1 or 0.36–0.52% y−1. This yield gain was associated with a linear increase in water-N co-limitation, in turn associated with an increase in N uptake per mm of evapotranspiration at a rate of 0.0019 kg N mm−1 y−1. Our findings highlight the critical role of nitrogen for the adaptation of wheat to low rainfall environments, and the scope for further yield improvement based on traits that integrate resources. [ABSTRACT FROM AUTHOR]

Insufficient nitrogen applications may contribute to yield gaps in low rainfall environments of Western Australia (WA). This study tested a nitrogen nutrition index (NNI) for wheat tailored for low rainfall regions, which is based on rainfall-scaled dilution curves. We analyzed yield, shoot biomass, and nitrogen concentration from 32 field trials in WA. An empirical rainfall threshold of 400mm (summerþgrowing season rainfall) returned two parallel dilution curves accounting for the reduction of critical N in drier and lower yielding conditions. Scatterplots of relative yield and rainfall-adjusted NNI returned a robust boundary function that may lead to greater adoption by growers. The NNI defined in this research study can be applied and further tested by growers in WA, but may also apply to other low rainfall environments, to close nitrogen related yield gaps. [ABSTRACT FROM AUTHOR]

Late-season nitrogen (N) application has been proposed to boost grain yield and grain protein concentration (GPC) in cereals; however, its effects on bread and durum wheat have been inconsistent in field experiments. We performed a meta-analysis to (i) assess the effect of N applications to wheat after flag leaf visible (GS 37) on grain yield and GPC; and to assess the variation in these responses with (ii) N fertiliser management, (iii) environmental factors, and (iv) physiological traits. We searched ' Agronomy Journal ', ' Crop Science ', ' European Journal of Agronomy ', and ' Field Crops Research ' for articles published between 1980 and 2021 that allowed for a direct comparison of wheat yield and GPC between N application after GS 37 to an otherwise equally managed crop that received basal N fertilisation. We also collected other traits such as stover biomass and N uptake at plant maturity, and dough rheological properties, when available. The search resulted in 38 articles that, in addition to one unpublished trial from our group, evaluated 542 pairwise comparisons in 127 environments. Across studies, grain yield ranged from 1.15 to 10.63 Mg ha−1 and showed a negative relation with GPC, which ranged from 65 to 189 g kg−1. Late-season N fertilisation was consistently neutral for grain yield (I2, proportion of the overall variance due to variation in real effects rather than chance, 26.2 %) and increased GPC with a pooled estimate of 3.96 %. The response of GPC was heterogeneous (I2 = 84 %), suggesting the need for exploration of potential moderators of the response. Meta-regression suggested that increasing the proportion of late N relative to the total available N positively associated to increases in GPC, and the residuals of this analysis suggested that later applications increased GPC response, with no effect of N fertiliser source or placement. Environments with low temperature, high photothermal quotient, and long duration of the critical period associated with greater GPC response to late-season N applications. The relative response of GPC to late fertilisation correlated with the relative response of both stover N uptake and nitrogen concentration in stover at maturity, but not with stover biomass at maturity. Alveogram index and dough extensibility increased when late-season N increased GPC. Enhancing GPC through late N applications should consider associations between management, environmental, and physiological factors. Future research should focus on forecasting GPC response to late N, based on GPC response drivers identified in the current research. • Meta-analysis highlighted physiological drivers of wheat response to late N • Grain yield was unaffected by late N across a broad range of environments • Late N increased protein by 3.96% and its effects were heterogeneous • Protein increased linearly with the proportion of late N and with later applications • Higher protein response to late N associated to favourable growing conditions [ABSTRACT FROM AUTHOR]

Rainfed crops rely on two sources of water: stored soil water at sowing and seasonal rain. In strongly seasonal winter-rainfall environments, stored soil water at sowing is minor, and uncertain seasonal rainfall is a source of risk. In south-eastern Australia, under-fertilisation is a common outcome of nitrogen risk management with implications for wheat yield and mining of soil organic matter. Here we explore the use of carbon isotope composition (δ 13C) to capture the effects of crop water status on grain yield in a context of nitrogen top dressing. In the sampled environments, crops receive at least 50% of seasonal rainfall by stem elongation, and at least 70% of seasonal rainfall by flowering. In a sample of 1518 plots, yield varied from 0.07 to 9.96 t ha-1 and correlated with δ 13C measured with isotope ratio mass spectrometer (IRMS) at flowering (r = −0.76, p < 0.0001); this is consistent with the rainfall pattern and the physiology of the crop featuring a critical period for yield from 300 °Cd before to 100 °Cd after anthesis. In a sample of 135 plots, yield varied from 1.2 to 8.4 t ha-1 and correlated with δ 13C measured with IRMS at stem elongation (r = −0.56, p < 0.0001). Yield response to nitrogen, defined as the difference between yield in fertilised crops (50–200 kg N ha-1) and unfertilised controls, correlated with δ 13C measured with IRMS at stem elongation, except for late-sown crops. Mid-infrared spectroscopy (MIR) returned estimates of δ 13C that agreed with δ 13C measured with IRMS (calibration: R2 = 0.82, RMSE = 0.53‰, n = 833; validation: R2 = 0.70, RMSE = 0.75‰, n = 364). We conclude that a MIR based, high-throughput, affordable measurement of δ 13C could be scaled to guide nitrogen management of wheat in winter-rainfall environments. • In a sample of 1518 plots, yield varied from 0.07 to 9.96 tha-1 and correlated with δ 13C at flowering. • Yield response to nitrogen correlated with δ 13C at stem elongation, except for late-sown crops. • Mid-infrared spectroscopy is a cost-effective, high-throughput approach to estimate δ 13C for agronomic applications. [ABSTRACT FROM AUTHOR]

Abstract: Yield components are relatively easy to measure and their interpretation is intuitive. However, strong environmental influences, genetic and physiological controls, and evolutionary constraints collectively lead to lack of independence among yield components that restrict their value in breeding and agronomic applications. Here, we first sketch a framework of plant responses to environmental factors to highlight the modulation of yield components by resources and their interplay with non-resource factors including developmental cues (e.g. maternal effects), extreme events (e.g. frost), predicting factors (e.g. photoperiod) and synchronising and integrating information (e.g. spectral composition of light). We suggest that, to the extent that non-resource cues allow plants to predict future availability of resources, simple resource-based models may be sufficient to capture the macroscopic responses of yield components to the environment. Next, we expand the original concept of hierarchy of plasticities between grain size (a relatively stable trait) and grain number (a plastic trait) to test the hypothesis of a broader hierarchy in the plasticities of yield components. Using published data for wheat, rice, barley and triticale, we verified that heritabilities capture the established hierarchy between plasticity of grain size and number. Median heritabilities of 0.31 for tiller number, 0.58 for inflorescence number, 0.59 for grains per inflorescence, and 0.79 for grain size supported the hierarchy of plasticities: tiller number > inflorescence number ≈ grains per inflorescence > seed size. The heritability of grain yield was consistently higher than the heritability for tillering, consistently lower than the heritability for grain size, and suggestively close to the heritability of inflorescence number and grains per inflorescence, the components of grain number per unit ground area. We conclude that understanding the environmental regulation of yield components in cereals would benefit from a dual focus on yield-related traits per se and their plasticity. [Copyright &y& Elsevier]

We used a water-centred framework (yield = transpiration × transpiration efficiency × harvest index) to investigate the effect of soil salinity on growth and yield of wheat and barley. Our working hypothesis is that salinity reduces transpiration proportionally more than transpiration efficiency. We established a glasshouse experiment with the factorial combination of four varieties (wheat: Janz, Krichauff; barley: Mundah, Keel) and three soil treatments: a control with no NaCl added, and NaCl added to achieve soil EC 0.75 dS m and 1.5 dS m. Pot-grown plants were watered to weight to determine transpiration and shoot dry matter was determined using a non-destructive image analysis system. Consistent with our hypothesis, salinity reduced transpiration (30-60%) proportionally more than transpiration efficiency (0-35%); transpiration accounted for 90% of the variation in shoot growth across varieties and treatments. Against this pattern, there were time- and variety-dependent responses. The rate of leaf appearance and the transpiration efficiency of Janz, Krichauff and Keel showed a two-stage response to salinity. In stage 1, salt-stressed plants maintained rate of leaf appearance and transpiration efficiency close to or slightly below those of the controls. After a clear break point where the slope changed, stage 2 was characterised by a substantial reduction in both traits. Stage 2 was not evident in salt-stressed Mundah, which maintained a relatively high rate of leaf appearance and transpiration efficiency. Across species, harvest index increased from 0.40 in controls to 0.47 at 0.75 dS m. Harvest index of plants grown at 1.5 dS m was unaffected in wheat, and was reduced in barley. We propose that an understanding of the effect of salinity on crop development, growth and yield requires integration of low-level traits in a framework of resource capture, resource-use efficiency and plant allocation. Osmotic stress tolerance, Na exclusion, and tissue tolerance to accumulated Na would improve yield of salt-stressed crops to the extent that these traits contribute to the maintenance of water uptake and harvest index. [ABSTRACT FROM AUTHOR]

• Splitting N in 3–4 applications improved wheat yield by 7 % and grain protein content by 5 %. • The effect of split N on yield was larger for winter wheat than for spring wheat. • Split N mitigated the negative relationship between yield and grain protein content. Management of nitrogen (N) fertilizer is critical to avoid the environmental consequences of both over-fertilization and excess reactive N in the system, and chronic under-fertilization and soil mining. Split N application seeks to improve nitrogen use efficiency in both small-holdings and large-scale mechanized farms, but lack of conclusive evidence on its benefits restricts the adoption of this practice. Here we report a global meta-analysis of split N application in wheat using 129 studies with 2661 comparisons. Split N in 3–4 applications improved yield by 7.0 % and grain protein by 5.2 % in relation to single application. The effect of split N on yield was larger for winter wheat than for spring wheat, while split N improved grain protein in both winter and spring wheat. Its effects on both yield and grain protein were larger under conventional tillage, in humid climate especially for winter wheat, in coarse textured soils, on less fertile soils, and at high N rate. Splitting N in 3–4 applications would increase annual production of winter wheat by 12.9 M t grain and 1.3 M t protein globally. By identifying the conditions where split N application is more likely to deliver agronomic benefits, our study would contribute to the targeted adoption of this practice. [ABSTRACT FROM AUTHOR]

Abstract: Whereas the concept that availability of resources drives seed production is sound in principle, it is incomplete as there are many solutions to the allocation of resources that derive from the trade-off between number and size. This paper examines evolutionary aspects of this trade-off in annual grain crops. The analysis is centred on the working hypotheses that, for a given species and environment, allocation of resources to reproduction involves (H1) high plasticity in seed number, which allows for variable resource availability, and (H2) a relatively narrow range of seed size that results from evolutionary and agronomic selection. Comparisons between crops and fish are used to highlight common evolutionary elements in taxa where parents provide little or no care to their offspring, with the consequence that both number and early survival of offspring, hence fitness of parents, are partially related to embryo size and reserves. The plasticity of seed number in relation to availability of resources is analysed against the established relationship between offspring number and parent growth rate during critical stages. The notion that seed size is under stabilising selection is analysed against three conditions: (1) mean seed size is conservative for a given species and environment, (2) seed size affects fitness, and (3) seed size is heritable. Databases from published papers were compiled to analyse the relative variability of seed size and number, and the heritability of seed size. Evidence for and against the link between seed size and parental fitness is revised using the Smith–Fretwell model as framework (Am. Nat., 108, 499–506). The proposal of high plasticity of seed number and narrow variability of seed size resulting from stabilising natural selection is generally consistent with evolutionary and genetic considerations. Agronomic selection may have reinforced natural selection leading to relatively narrow seed size in species such as wheat and soybean, where cultivated types retained high plasticity for seed number. In contrast, selection for one or few inflorescences in crops like sunflower and maize may have morphologically reduced seed number plasticity and increased variability of seed size and its responsiveness to resource availability in relation to their wild ancestors. [Copyright &y& Elsevier]

• Yield gaps for temperature-limited yield potential Y T varied with location, time of sowing, cultivar and nitrogen. • Y T related negatively to mean temperature in the critical period returning a slope of -0.53 t ha−1 °C−1. • Elevated temperature reduced the duration of the critical period and was the largest driver of reduced grain number and yield. • Yield-temperature relationships crossed over in the response to nitrogen fertilisation. Elevated temperature, water deficit, low nitrogen availability and their interactions, constrain wheat yield in Mediterranean-type environments. Our working hypothesis is that, owing to the non-linearity of yield response to water and nitrogen and the non-linearity of biological processes in response to temperature, the outcome of the interactions between temperature, nitrogen and water is range-dependent. To generate a broad range of conditions in testing this hypothesis, we established two experiments. Experiment 1 combined factorially four sowing times, six cultivars and four nitrogen rates in four locations-seasons. Experiment 2 combined factorially two cultivars, two nitrogen rates, and two thermal regimes to further untangle interactions. Thermal regimes were unheated controls, and crops heated with passive open-top heating chambers increasing temperature by 0.5 °C during grain set or grain filling. Across the 384 combinations of treatments in Experiment 1, yield ranged between 0.12 t ha-1 and 5.96 t ha-1. The duration of the critical period (300 °C d before anthesis to 100 °C d after anthesis) decreased with mean temperature at an average rate of 5 d °C-1 and accounted for 75% of the variation in yield. We used quantile regression to calculate a temperature-limited yield potential Y T and derived a linear function between Y T and mean temperature in the critical period, returning a slope of -0.53 t ha-1 °C-1. Yield gap, i.e., the difference between Y T and actual yield, was larger in nitrogen and water-deficient crops. Yield-temperature relationships crossed over in response to nitrogen fertilisation. Fertilised crops (100−200 kg N ha-1) outyielded their unfertilised counterparts when mean temperature during the critical period was below 13 °C, and unfertilised controls were superior above this threshold. Locally calibrated thresholds can be used as a rule-of-thumb adding a further dimension to the management of combined stresses and risk of wheat in Mediterranean-type environments. In Experiment 2, yield responded to the interaction between temperature and nitrogen, whereby elevated temperature during grain set reduced yield by 17% in unfertilised crops with no effect on crops with 100 kg N ha-1. Elevated temperature during grain fill reduced yield by 14% with no effect of nitrogen or nitrogen x temperature interaction on grain yield. [ABSTRACT FROM AUTHOR]

• Selection for yield favours low competitive ability. • Hypothesis: the yield-nitrogen curve mirrors the competition-nitrogen curve. • Hypothesis held in early sown crops where switch in resource competition occurs from N to radiation and water when increasing N availability. • In late-sown crops fast development outweighed competition as driver of yield. • Genetic and agronomic reduction of intraspecific competition could improve nitrogen use efficiency. Agronomic and breeding innovations are essential to support grain production whilst avoiding over-fertilisation and excess reactive nitrogen in some agroecosystems, and chronic under-fertilisation and mining of soil organic matter in others. Based on the well-established negative correlation between yield per unit land area and intraspecific competitive ability, we hypothesised that the yield-nitrogen curve at the centre of fertiliser decisions mirrors the competition-nitrogen curve. A factorial study combining six wheat cultivars, two locations, two sowing dates and four nitrogen rates supported our hypothesis in early-sown crops where intraspecific competition for nitrogen decreased, and competition for radiation and water increased with increasing availability of nitrogen. In late-sown crops, high temperature favouring fast development, short plants and smaller canopies overrode competition for resources as the driver of grain yield. The implication is that genetic and agronomic reduction of intraspecific competition can improve yield per unit available nitrogen. [ABSTRACT FROM AUTHOR]

• Benchmarks of wheat N utilisation efficiency (NUtE) in Mediterranean conditions are needed. • We compiled a large set of data from Mediterranean and non-Mediterranean environments of Europe. • Mediterranean growing conditions narrowed N uptake contributing to lower final yields than in N Europe. • But they also reduced consistently NUtE (considering both average and maximum yields at each level of N uptake). • These effects on NUtE produced a trade-off with grain N concentration. Water and temperature stress during critical periods of grain yield formation are distinctive of wheat crops in Mediterranean environments. However, nitrogen (N) availability may also constrain grain yields in these environments. Benchmarks of yield response to N uptake in Mediterranean conditions are lacking, and extrapolation from non-Mediterranean environments is not warranted. We hypothesised that under Mediterranean environments (1) maximum N uptake would be lower, thus the range of N uptake would be narrower, and (2) N utilisation efficiency (NUtE, yield per unit N uptake) would be reduced along the whole range of N uptake than under non-Mediterranean conditions. To test these hypotheses, we compiled published data of yield and N uptake from Mediterranean (n = 340) and non-Mediterranean environments (n = 563) of Europe. Wheat in Mediterranean environments had lower average grain yield (4.1 vs 7.1 Mg ha−1), lower average N uptake (131 vs 166 kg N ha−1), lower average NUtE (33 vs 47 kg grain kg N−1), and higher average grain N concentration (2.4 vs 1.8%) than crops in non-Mediterranean environments. Boundary functions relating yield and nitrogen uptake captured the lower yield of wheat along the whole range of N uptake as hypothesised; these functions could be used for benchmarking wheat crops in Mediterranean regions of Europe, and possibly other Mediterranean environments. [ABSTRACT FROM AUTHOR]

Low temperature during the critical period of wheat can cause floret sterility, grain abortion, yield reduction, and economic losses. We tested the hypothesis that selection for yield improved frost tolerance. We measured phenology, yield and its components, including the distribution of grains within the spike, in a factorial experiment combining 12 wheat varieties released from 1973 to 2015, two sowing dates (mid-April and early or mid-May), two thermal regimes, ambient control and frost-protected, and two seasons. To protect crops from frost we used moveable, lightweight passive heating chambers before each frost event (≤ 0 °C). The rate of genetic gain in yield aligned with frost severity: it ranged from negligible under severe frost to 0.79 ± 0.05% y−1 in unfrosted crops. The chambers diminished but did not fully prevent frost; across sources of variation grain yield was 179 ± 20.1 g m−2 in ambient control and 264 ± 13.3 g m−2 in frost-protected treatments. Frost intensity was calculated as the cumulative, canopy-level minimum temperature below 2 °C during the period from −300 to + 100 °C d centred at anthesis. For the pooled data, yield declined with frost intensity at 1.24 ± 0.12% °C−1. Across varieties and environments, frost-protected crops set 29 ± 3.0 grains spike−1 compared with 19 ± 2.7 in ambient control. We did not find random grain abortion within spikelets, but random sterile spikelets. Average grain weight (weighed by the relative contributions of these grains to the number of grains per spike) in main shoot spike did not vary with thermal regime. Selection for yield did not improve frost tolerance. Preventing spring radiation frost improved spike fertility by increasing the proportion of grains in distal positions with no reduction in grain weight potential within spikelets in relation to controls. We advanced damage functions relating yield and frost, which are useful for modelling, and maps of grain set in spikes that help understanding the physiology of yield in response to frost. • We advance damage functions relating yield and frost, which are useful for modelling. • We quantified frost intensity as the cumulative minimum temperature below 2 ℃ during the critical period. • Wheat grain yield declined, on average, at 1.24% °C−1 with frost intensity. • The rate of genetic change in yield, from 1973 to 2015, declined with frost severity. • Frost-protection improved the proportion of grains in distal positions with no reduction in grain weight. [ABSTRACT FROM AUTHOR]

Winter crops are the backbone of Australian agriculture. This study reports the first comparative analysis of the impact of temperature and water stress on yields of wheat, barley, canola, chickpea and field pea across four major production zones in Australia (North, East, South and West) using the 2009-2013 National Variety Trials (NVT). Developmental windows of 100 °Cd centred at flowering were used to sample rainfall, vapour pressure deficit (VPD), potential evapotranspiration, water supply/demand ratio, average minimum (Tmin) and maximum (Tmax) temperature, number of days below 0 °C and above 30 °C, incident radiation, photothermal quotient (PTQ) and PTQ corrected by VPD. Flowering was estimated for a mid-season cultivar for each trial using a simulation model (APSIM). There was a consistent negative association between Tmax and yields in all crops, from early in the season in the South and after flowering in the West. Our study supports that high temperature in the non-stressful range is associated with yield reduction with crop specific effects. Days exceeding 30 °C were unlikely before flowering; wheat and chickpea were sensitive to temperatures above 30 °C from early and late in grain filling respectively. Chickpea was sensitive to low temperatures from flowering. Canola was overall the most sensitive to water stress. Unequivocally, the interaction between temperature and water stress exhibited strong regional differences. In the West, with Mediterranean rainfall pattern, high Tmin before flowering was associated with higher yields in wheat, barley, canola and chickpea, indicating a role in promoting early growth and water use and reducing evaporation. In the North, crops depend on initial soil moisture, and high yields were associated with lower Tmin, likely slowing growth and early water use and lessening terminal stress. These relationships need direct experimental confirmation to show causality but there is room for large scale studies to uncover seasonal and regional patterns and highlight targets for research, breeding and management options aimed at improving yield under climate change. [ABSTRACT FROM AUTHOR]