Field crops are expected to be increasingly threatened by climate change, which will negatively impact plant development, growth and yield. Phytohormones play a crucial role in regulating specific signalling pathways to induce rapid adaptive responses to environmental stresses. Exogenous phytohormone application alters hormonal balance, thereby enhancing plant adaptation to adverse conditions. While several studies have advanced our understanding of the use of phytohormones in field crops, yield responses and species-specific application strategies remain inconsistent and rarely assessed under field conditions. The application of cytokinins (CKs), abscisic acid (ABA), and gibberellic acid (GA) has been shown to maintain prolonged photosynthetic activity, stabilize plasma membrane, and reduce lipid peroxidation and ion accumulation under salinity stress in wheat. Additionally, inhibitors of ethylene synthesis and receptors can mitigate stress symptoms under drought and heat stress, which typically accelerates senescence and shortens the grain-filling period in cereal crops. In this way, exogenous application of CKs, GA, and ethylene inhibitors can delay senescence by sustaining leaf photosynthetic activity and postponing nutrient remobilization. However, these benefits may not consistently translate into improvements in grain yield and quality. This review explores the molecular mechanisms of phytohormones in abiotic stress tolerance, delineates their specific functions and evaluates experimental findings from field applications. It also summarizes the potential of phytohormone applications in field crops, emphasizing the need for species-specific investigations on application timing and dosages under open-field conditions to optimize their agronomic potential.

Current agriculture intensifies crop cultivation to meet food demand, leading to unsustainable use of chemical fertilizers. This study investigates a few physiological and agronomic responses of common wheat following the inoculation with plant growth-promoting bacteria to reduce nitrogen inputs. A field trial was conducted in 2022–2023, in Legnago (Verona, Italy) on Triticum aestivum var. LG-Auriga comparing full (180 kg ha⁻¹) and reduced (130 kg ha⁻¹) N doses, both with and without foliar application at end tillering of the N-fixing bacterium Methylobacterium symbioticum. Biofertilization did not improve shoot growth, while it seldom increased the root length density in the arable layer. It delayed leaf senescence, prolonged photosynthetic activity, and amplified stomatal conductance and PSII efficiency under the reduced N dose. Appreciable ACC-deaminase activity of such bacterium disclosed augmented nitrogen retrieval and reduced ethylene production, explaining the ameliorated stay-green. Yield and test weight were unaffected by biofertilization, while both glutenin-to-gliadin and HMW-to-LMW ratios increased together with dough tenacity. It is concluded that Methylobacterium symbioticum can amplify nitrogen metabolism at a reduced nitrogen dose, offering a viable approach to reduce chemical fertilization under suboptimal growing conditions for achieving a more sustainable agriculture. Further research over multiple growing seasons and soil types is necessary to corroborate these preliminary observations.

Current agriculture intensifies crop cultivation to meet food demand, leading to unsustainable use of chemical fertilizers. This study investigates a few physiological and agronomic responses of common wheat following the inoculation with plant growth-promoting bacteria to reduce nitrogen inputs. A field trial was conducted in 2022-23, in Legnago (Verona, Italy) on Triticum aestivum var. LG-Auriga comparing full (180 kg ha-1) and reduced (130 kg ha-1) N doses, both with and without foliar application at end tillering of the N-fixing bacterium Methylobacterium symbioticum. Biofertilization did not improve shoot growth, while it seldom increased root length density in the arable layer. It delayed leaf senescence, prolonged photosynthetic activity, amplified stomatal conductance and PSII efficiency under reduced N dose. Appreciable ACC-deaminase activity of such bacterium disclosed augmented nitrogen retrieval and reduced ethylene production, explaining ameliorated stay-green. Yield and testing weight were unaffected by biofertilization, while both glutenin-to-gliadin and HMW-to-LMW ratios increased together with dough tenacity. It is concluded that Methylobacterium symbioticum can amplify nitrogen metabolism at reduced nitrogen dose, offering a viable approach to reduce chemical fertilization under suboptimal growing conditions for achieving a more sustainable agriculture. Further research over multiple growing seasons and soil types is necessary to corroborate these preliminary observations.

The increasing frequency of heat waves and drought during wheat ripening undermines yield potential and grain quality by accelerating plant senescence. This study investigated the effects of late foliar cytokinin (6-benzyladenine, 6-BA) application timing and dosage on leaf greenness, photosynthesis, yield, and grain quality in open-field wheat cultivation in NE Italy. Four application timings were evaluated: at flowering (T1), and at 10 (T2), 20 (T3), and 30 (T4) days after flowering, and two double applications (T1+T3; T2+T3), at three 6-BA doses (25, 50 and 150 g ha^-1) compared with untreated controls (C). T1 application significantly prolonged canopy greenness (p ≤ 0.05), while increases in CO₂ assimilation (+15 %) and yield (+6 %) were non-significant. Grain protein content improved significantly, and gluten composition shifted toward a higher glutenins/gliadins ratio. Later applications, especially T3, significantly increased leaf chlorophyll content, the glutenins/gliadins ratio, and low-molecular-weight glutenins, whereas double applications mainly enhanced root development in the upper soil profile (+20 to +33 %) without yield benefits. T2 and T4 were largely ineffective for canopy greenness, but showed selective positive effects on protein or root traits. Overall, yield responses remained non-significant, but cytokinin effects were stage-dependent, with treatments at flowering providing the most consistent benefits at doses ≥50 g ha^-1. Taken together, these findings support a dual-role model of cytokinin action: early 6-BA sprays delay senescence and enhance N remobilization, while later sprays alter gluten composition, highlighting the potential of cytokinin treatments to improve wheat resilience and quality under field conditions; validation across environments and genotypes is still required.

Conventional spring sowing of sugar beet in Europe faces increasing constraints from summer drought, high temperatures, and Cercospora beticola pressure due to climate change. This two-year field trial (2021–2022 and 2022–2023) evaluated the feasibility of autumn-sown sugar beet at a northern Mediterranean site in Legnaro (Padua, NE Italy, 45°21′ N). Nine varieties were assessed across four sowing dates in 2021 (late September to early November) and two sowing dates in 2022 (late September and late October). Measurements included overwinter survival, bolting incidence at two reproductive stages, fresh root and above-ground biomass yield at sequential harvest dates, and root soluble solids (°Brix). Post-winter mortality was negligible following September and early-October sowings, moderate after late-October sowings (17.3% in 2021; 13.2% in 2022), and extremely high after early-November sowing (81.5%). These patterns indicated that winter survival was more strongly determined by crop developmental stage before winter than by seasonal minimal temperatures recorded in two seasons (−3.6 °C and −6.3 °C, respectively). Bolting incidence showed the opposite trend, reaching near-complete or complete expression in the earliest sowings regardless of variety choice. In late-October sowings, clear varietal differences emerged. Some varieties combined low bolting incidence with high root yields, reaching 81.1–84.4 t ha⁻¹ at the final harvest (early August 2023). Root juice soluble solids were higher in the drier 2021–2022 season (exceeding 20 °Brix in several cases) than in the wetter 2022–2023 season (consistently below 17.5 °Brix), reflecting dilution effects associated with the different seasonal precipitation. In the sequential harvest series of late-October 2022 sowing, later harvest dates were generally associated with lower soluble solids. These results indicate that, within the autumn sowing window evaluated, late-October sowing combined with appropriate varietal selection provided the best balance between overwinter survival, bolting incidence, and root yield at this northern Mediterranean latitude. Future multi-site studies, including spring-sown controls, could enable direct comparison with conventional sowing practice.