Waterlogging is a severe abiotic stressor causing significant growth impairment and yield losses in many crops. Maize is highly sensitive to the excess of water, and against the background of climate change there is an urgent need for deeper insights into the mechanisms of crop adaptation to waterlogging. In the present study, changes in maize morphology at the 4–5 leaf stage and the expression of three candidate genes for flooding tolerance in plants subjected to six continuous days of waterlogging were recorded in 19 commercial hybrids and in the inbred line B73, with the aim of investigating the current variability in cultivated hybrids and identifying useful morphological and molecular markers for screening tolerant genotypes. Here it was demonstrated that root parameters (length, area, biomass) were more impaired by waterlogging than shoot parameters (shoot height and biomass). Culm height generally increased in stressed plants (by up to +24% vs. controls), while shoot biomass was significantly reduced in only two hybrids. Root biomass was reduced in all the hybrids, by an average of 30%, and significantly in 7 hybrids, while root length and area were even more severely reduced, by 30–55% vs. controls, depending on the hybrid. The earlier appearance of aerial roots seemed to be associated with greater root injuries. In leaves, the transcript of the PFP enzyme (phosphofructokinase), which is involved in glycolytic reactions, was markedly up-regulated (up to double the values) in half the waterlogged hybrids, but down-regulated in the others. The transcript of CYP81D8 (ROS-related proteins) in waterlogged plants exhibited relevant increases or strong decreases in level, depending on the hybrid. The transcript of the AOX1A gene, coding for a mitochondrial respiratory electron transport chain-related protein, was markedly down-regulated in all the treated hybrids. Expression analysis of these genes under extreme waterlogging only partially correlate with the shoot and root growth impairments observed, and AOX1A seems to be the most informative of them.

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.

Root characteristics and metal uptake in the maize hybrid Naudi were studied in a pot trial, using soil artificially highly polluted with Zn, Cu, Co, Cd, and Pb. The addition of these metals as sulfates decreased the soil pH and increased electrical conductivity. As a result of increased bioavailability in the soil pore water, significantly higher concentrations of metals, particularly Pb, Cu, and Co, were found in the shoot tissues of maize at the 3–4 leaf stage. While the lowest increase was in Cd (0.89 mg kg⁻¹ vs. 0.33 mg kg⁻¹ for controls), Zn reached a critical threshold of 75 mg kg⁻¹ vs. 2.76 mg kg⁻¹. Fresh and dry weights of shoots and roots, as well as root length, were markedly reduced, whereas root diameter, tip density, and the branching index increased considerably. A significant adaptation strategy by maize in the polluted soil was an increased fraction of coarse root length and a decreased fraction of finer roots. We conclude that maize is very sensitive to multiple metal pollution, suggesting its potential use as a test plant to evaluate contaminated soils. As length was the most affected root characteristic, measurement of this parameter could be a way of screening genotypes for tolerance to metal contamination and possibly salinity. There also is future scope for investigating whether K fertilization might mitigate metal phytotoxicity, in view of the negative correlations between the shoot K concentration and concentrations of the supplied metals.

Late-season N application through foliar spraying is recognized as an efficient agronomic practice for improving grain quality in common wheat, although the major part of N is still supplied by soil fertilization. This study assessed the impact of various N doses entirely applied by repeated foliar sprayings on wheat growth, yield and quality, in comparison with conventional soil fertilization management with a recommended dose of 160 kg N ha⁻¹ as ammonium nitrate (C-M). Doses of 96, 104 and 120 kg N ha⁻¹ as both UAN (urea-ammonium-nitrate) and urea applied by foliar spraying were evaluated in a 2-year field trial in Northern Italy in a silty loam soil with 1.7% organic matter. Here, it was demonstrated that the canopy greenness was similar in all treatments, with slight grain yield increases by the lowest foliar N dose vs. C-M. The higher N foliar doses mainly improved the grain protein content and both high- and low-molecular-weight glutenin subunits (HMW-GS, LMW-GS), particularly with urea. It is concluded that in our fertile soil, managing N fertilization exclusively through foliar spraying is feasible without compromising grain yield and ameliorating quality at the same time. Improved nutrient use efficiency and beneficial environmental effects are also expected by reducing the nitrogen load on the agricultural fields by 25–40%.

Tritordeum is a novel hexaploid cereal derived from the cross between a wild Chilean barley species (Hordeum chilense Roem. et Schultz) and durum wheat (Triticum turgidum ssp. durum Desf.) that is potentially of great interest for human nutrition. In this study, a commercial and an experimental Tritordeum cultivar were analyzed in comparison with a reference durum wheat under conventional and organic management. We demonstrate that Tritordeum is better adapted to organic farming through an increase in the below-ground rhizosphere community of the Bacteroidetes phylum, which includes many bacteria species known to exert beneficial effects on plants, particularly for root growth. Despite a considerably lower grain yield, Tritordeum had better quality traits than durum wheat, particularly under organic farming vs. conventional management, with respect to total protein contents, high molecular weight glutenin subunits, antioxidant free phenols and nutrients (i.e., calcium, potassium, sulphur, iron, and zinc), depending on the cultivar. We conclude that Tritordeum is a promising cereal in light of its quality traits and adaptability to sustainable crop management practices, such as organic farming, although further improvement in yield potential should be pursued by breeding and by optimising the cultivation method.