Bean (Phaseolus vulgaris L.) is one of the most cultivated and consumed legumes worldwide. Brazil is one of the world's largest producers of this crop, which constitutes an important primary source of protein in the diet of its population. In the Northeast region, this legume is a key crop, especially for small family farmers. However, this region has high production susceptibility, which is mainly due to local climatic conditions and the low degree of technification employed. In this sense, the objective of this study was to analyze the productive variations of the bean crop in the municipality of Dois Riachos, Semi-arid of Alagoas, in the period 1998-2015. The production data were obtained from the IBGE Municipal Agricultural Production database, using the Automatic Recovery System (SIDRA), and subjected to correlation analysis and principal component analysis (PCA). The results showed high interannual variability in the production of beans, reflected in the strong oscillation of the analyzed variables. Significant correlations were observed between all variables. The PCA gathered 93.8% of the original data variance in its first two axes, generating 4 clusters that grouped years with similar productive characteristics. The reductions observed for the variables may be linked mainly to abiotic factors, such as the occurrence of prolonged droughts, and the low degree of technification used for this culture.

The salinity of irrigation water or soil is the abiotic factor that most negatively impacts the yield of crops, including green maize, so it is necessary to find alternatives to ensure production. In this context, this study aimed to evaluate gas exchange, photosynthetic pigments, and growth of maize under salinity of irrigation water and application of hydrogen peroxide. The experiment was conducted at the Center of Sciences and Agrifood Technology, Pombal, PB, belonging to the Federal University of Campina Grande, in the period from January to February 2015, using the maize hybrid ‘AG 1051’. The treatments consisted of two salinity levels of irrigation water (0.3 and 2.0 dS m-1) and five concentrations of hydrogen peroxide (0, 40, 80, 160, and 320 µmol L-1) applied via irrigation water. The experimental design was completely randomized, in a 2 × 5 factorial scheme, with four replicates. ECw of 2.0 dS m-1 reduces transpiration, stomatal conductance, total chlorophyll, carotenoids, and initial growth, but does not affect the dry mass accumulation of maize plants. Application of H2O2 via soil varying from 0 to 320 µmol L-1 causes reductions in the CO2 assimilation rate and transpiration, as well as at concentrations from 0 to 160 µmol L-1 for stomatal conductance of plants irrigated with ECw of 2.0 dS m-1. Application of H2O2 via soil up to a concentration of 320 µmol L-1 increases the plant height, but reduces culm diameter of maize.

Although the semi-arid region of Northeast Brazil is a major producer of yellow passion fruit, the problems of salts in the soil and water sources, in many areas have limited the growth and production of this crop, which highlights the importance of studies aimed at reducing such effects. In this context, the objective of this study was to evaluate the effect of foliar application of pyruvate, as a mitigator of salt stress, on the morphophysiology of yellow passion fruit, in seedling phase. The treatments consisted of three electrical conductivities of irrigation water (ECw: 0.8, 2.4, and 4.0 dS m-1) and three concentrations of pyruvate (0, 25, and 50 mM), distributed in a randomized block experimental design in a 3 × 3 factorial scheme, with four replications and two plants per plot. Irrigation with ECw of 4.0 dS m-1 reduces growth variables, phytomass, Dickson quality index, and increases electrolyte leakage in passion fruit seedlings cv. Redondo Amarelo. Exogenous application of calcium pyruvate (25 and 50 mM) increased growth, phytomass, Dickson quality index, relative water content and leaf succulence and reduced electrolyte leakage in the leaf blade in passion fruit. Exogenous application of pyruvate attenuates salt stress, with beneficial effects on CO2 assimilation rate, transpiration, instantaneous carboxylation efficiency, intrinsic water use efficiency, and root dry mass.

Salinity is among the biggest challenges of irrigated agriculture, as it induces several limitations to the growth and physiology of plants; therefore, strategies should be sought that minimize its impacts on plants. In this scenario, the present study was developed to examine the effects of different salicylic acid (SA) application methods on photosynthetic pigments, chlorophyll a fluorescence, gas exchange, and biomass accumulation of cherry tomato under salt stress. The study was carried out in a greenhouse, using a Regosol soil (Psamments) with a sandy-loam texture. The treatments were distributed in a completely randomized design, in a 2 × 4 factorial arrangement consisting of two levels of electrical conductivity in the irrigation water (0.6 or 2.6 dS m-1) and four salicylic acid application methods (M1 = without SA [control] application; M2 = foliar spray; M3 = irrigation; or M4 = spray and irrigation), with five replicates. Irrigation with 2.6 dS m-1 salinity water negatively affected chlorophyll a fluorescence and the total chlorophyll, chlorophyll a, and carotenoid contents, in addition to inhibiting stem dry biomass production and root/shoot ratio. Foliar spray with salicylic acid minimized the deleterious effects of salt stress on gas exchange and chlorophyll content and increased leaf and root dry biomass accumulation and the root/shoot ratio of cherry tomatoes at 120 days after sowing.

Sugarcane is one of the largest agricultural commodities when considering the export volume and the number of jobs generated. Sugarcane production in the Brazilian Northeast region is generally low due to several factors, including the irregular rainfall distribution, which highlights the importance of studies aimed at mitigating the deleterious effects of water stress. In this scenario, this study aimed to evaluate calcium pyruvate as a water deficit attenuator on the agro-industrial quality of sugarcane in the second cycle of cultivation. The experiment was conducted out under greenhouse conditions of the Federal University of Campina Grande, where five sugarcane commercial genotypes tested (G1- RB863129, G2- RB92579, G3- RB962962, G4- RB021754, and G5- RB041443) and three irrigation management strategies (E1- full irrigation, E2- water deficit with application of 30 mM of calcium pyruvate, and E3- water deficit without calcium pyruvate application), distributed in randomized blocks in 5 × 3 factorial arrangement with three replications. The RB021754 genotype under water deficit and without foliar application of calcium pyruvate increased the fiber content (13.2%) and the sugarcane moist cake weight (143.5 g). The effects of water deficit in sugarcane genotypes are attenuated by the exogenous application of 30 mM of calcium pyruvate, with benefits on the polarized sucrose content, apparent sucrose content of the juice, soluble solids content, purity, corrected cane POL, total recoverable sugars, and stem mass in relation to plants under water deficit without calcium pyruvate application.

The lack of water during crop growth causes damage to any production system, especially when it occurs during the initial establishment or beginning of the reproductive stage. Although cotton can be properly managed in regions with water limitation, its yield is affected at different levels according to the genetics of the cultivar adopted. Exogenous application of some organic components has shown a stress-mitigating effect and can be a valuable procedure to enhance the yield of water stress-sensitive cultivars. The objective of this work was to evaluate the benefits of exogenous application of pyruvic acid (100 µM) in cotton plants under water deficit varying the phenological stage of the crop. The experiment was conducted in a greenhouse, where the plants were grown in pots and subjected to seven days of water suspension, initiated individually in stages V2 and B1. Each pot contained two plants. The treatments adopted were: T1 - control, T2 - water suppression; and T3 - water suppression + pyruvate application. The design was randomized blocks in a factorial scheme (3 × 3) with three replicates. The reductions in gas exchange and growth of the cultivars BRS Seridó, CNPA 7MH and FM 966 were more significant in the reproductive stage, especially for FM 966, which was more sensitive. Pyruvate application reduced the effects of water suppression on boll production by 31% in BRS Seridó and 34% in CNPA 7MH and FM 966.