Os mapas de produtividade refletem na maior parte das vezes a variação espacial e temporal dos diferentes fatores condicionadores do processo produtivo, sendo que o conhecimento de tais variações é importante na tomada de decisão desse mesmo processo produtivo. Neste estudo pretendemos identificar e caraterizar a variabilidade espacial e temporal (4 anos) da produtividade de milho, considerando para tal uma parcela regada por um Center Pivot e utilizando a técnica multivariada de análise de componentes principais. A aplicação da análise de componentes principais aos dados multitemporais da produtividade de milho permitiu perceber que: i) o 1º componente está relacionado com a produtividade média temporal, podendo a partir desta e dos respetivos loadings, perceber se a variabilidade temporal da produtividade média é baixa ou alta; ii) o 2º componente identifica as manchas da parcela com maior ou menor resiliência à variação temporal da produtividade; e iii) o 3º componente, fornece-nos pois a carta da estabilidade temporal da produtividade.The yield maps reflect in most cases the spatial and temporal variation of the different conditioning factors of the production process, so the knowledge of such variations is important in decision making of that same production process. In this study we intend to identify and characterize the spatial and temporal variability (over 4 years) of maize yield, considering for such a parcel irrigated by a center pivot and the multivariate technique of principal components analysis. The application of principal components analysis to a multitemporal data of maize productivity allowed to realize that: i) the 1st component is related to the average productivity of time and from this and the respective loadings we can see if the temporal variability of the average productivity is low or high; ii) the 2nd component identifies the portion of parcel more or less resilient to temporal variation, iii) the 3rd component provides us the maps of the temporal stability of productivity.

The main objective of this work is to compare different testes to evaluate for combining ability a group of unselected lines. Twenty eight lines from the CMS 04C population and six testers were used. The testers were the BR105 population, three imbreed lines from the BR105, one single cross proceeding from crossing of two of the used lines as testers and the EMGOPA 501 population. Because of the limited amounts of seeds, the topcrosses of the 20 from the 28 lines were evaluated in two places. The incomplete block design with two common treatments and three replicates were used for the topcrosses evaluation. The trials were installed in 2000/01 season, in the experimental stations of the Planagri company, in Goianésia-Goiás, and at the Escola de Agronomia of Universidade Federal de Goiás, in Goiânia-Goiás.The diallel analysis followed the model of Griffing (1956), adapted by Geraldi & Miranda Filho (1988). The correlations of Spearman, percentage of coincidence based in selection intensity and the variances between topcrosses were used, to compare the testers. It wasn’t observed consistency of the lines rank among the testers and not even for each tester between the two places. The results were different for each place. In Goianésia, the BR105 population, that got greater estimative of General Combining Ability, was the most convenient tester to discriminate the lines. However, in Goiânia, the EMGOPA 501 population, that got the lowest estimative of General Combining Ability, was the most convenient tester to evaluate the lines. In the combined analysis of the two places, the EMGOPA was only able to discriminate the lines. Some lines were superior in hybrid combining and some crossings will have to be evaluated in other environments to confirm its good performance.

Phosphorus plays a crucial role in plant growth, influencing vital processes such as photosynthesis, respiration and the synthesis of nucleic acids. However, plants can only utilise phosphorus in the form of orthophosphate. Most of the phosphorus in the soil is in forms that are difficult to assimilate. Farmers often use chemical fertilisers to provide soluble phosphorus. This continuous behaviour will lead to the depletion of natural phosphate reserves and higher prices, increasing costs for the farmer and subsequently the consumer. In addition, the continued accumulation of phosphorus compounds in the soil contributes to soil and water pollution. The problem is exacerbated by the formation of phosphorus complexes in alkaline soils, in the form of calcium phosphate, and in acidic soils, in the form of aluminium/iron phosphate. A sustainable alternative to increase phosphorus availability for plants is the use of phosphorus solubilising bacteria (PSB) as biostimulants and biofertilisers. The aim of this study was to assess the ability of various bacterial strains from different areas (mainland Portugal, Sal Island (Cape Verde), Huíla (Angola) and the Namib Desert (Angola)) to solubilise phosphorus. After initial characterisation, some strains were selected for greenhouse tests and applying them individually to soils with pH 7 and 8. Subsequently, the most promising strains were tested in a consortium in field trials, using maize (Zea mays L.) as a model crop, given its contribution as a key cereal for global food security. In addition, the antioxidant response (superoxide dismutase and catalase activity), metabolic activity (electron transport system and soluble proteins) and how these bacteria influence the absorption of nutrients by plants were investigated. The results of this study are relevant in a context of growing environmental pressure and climate change and could contribute to the development of more productive and ecological agricultural methods, reducing the use of chemical fertilisers and protecting the environment.

Gelatinization and retrogradation of starch was followed in real time with an acoustic wave sensor. This study relies on the monitorization of the frequency of oscillation of a piezoelectric quartz crystal in contact with a 2.5% emulsion of a commercial maize starch, during heating and cooling. The technique showed to be very powerful and sensitive to most of the changes described in the literature, which have been elucidated by some other techniques. The value for the temperature of gelatinization found using the sensor was confirmed by the analysis of the same starch emulsion by polarized light microscopy. Temperatures of gelatinization were found to vary with the sample heating rate, as follows: 73.5 C at 2.0 C/min, 66.0 C at 1.0 C/min, and 65.0 C at 0.5 C/min. Hysteresis of the studied system was evidenced by the frequency shift before heating and after cooling till the initial temperature. Analysis performed on a 1.5% emulsion of a rice starch heated at 2.0 C/min and cooled as before, evidenced no hysteresis and showed complete reversibility, in which concerns to the series frequency of the piezoelectric quartz crystal.

This paper demonstrates the potential of using Web search volumes for generating crop specific planting and harvesting dates in the USA integrating climatic, social and technological factors affecting crop calendars. Using Google Insights for Search, clear peaks in volume occur at times of planting and harvest at the national level, which were used to derive corn specific planting and harvesting dates at a weekly resolution. Disaggregated to state level, search volumes for corn planting generally are in agreement with planting dates from a global crop calendar dataset. However, harvest dates were less discriminatory at the state level, indicating that peaks in search volume may be blurred by broader searches on harvest as a time of cultural events. The timing of other agricultural activities such as purchase of seed and response to weed and pest infestation was also investigated. These results highlight the future potential of using Web search data to derive planting dates in countries where the data are sparse or unreliable, once sufficient search volumes are realized, as well as the potential for monitoring in real time the response of farmers to climate change over the coming decades. Other potential applications of search volume data of relevance to agronomy are also discussed.

We provided an inventory of all arthropods recorded in four Azorean agroecosystems (citrus orchards, low and high elevation maize fields and vineyards) from Terceira Island. A total of 50412 specimens were collected, belonging to four classes, 20 orders, 81 families and 200 identified species of arthropods. A total of 127 species are considered introduced (n = 22646) and 69 native non-endemic (n = 24117). Four endemic species were recorded with very few specimens (n = 14) and 3635 specimens belong to unidentified taxa recorded only at genus or family level. Five species are new records for Terceira Island, with Lagria hirta (Linnaeus, 1758) (Coleoptera, Tenebrionidae) being also a new record for the Azores. This publication contributes to a better knowledge of the arthropods communities present in agro-ecosystems of Terceira Island and will serve as a baseline for future monitoring schemes targeting the long-term change in arthropod diversity and abundance.

ABSTRACT: The dataset presented here is an achievement of the H2020 European project "Integrated Pest Management of the Invasive Japanese Beetle, Popillia japonica (IPM-Popillia)". This project addresses the challenge of a new risk to plant health in Europe, the invasion of the Japanese beetle, Popillia japonica (Newman, 1838) (Coleoptera, Rutelidae) and provides an environmentally friendly IPM Toolbox to control the expanding pest populations across Europe. This study aims to present the records of terrestrial arthropod diversity with a special focus on four groups belonging to Carabids and Staphylinid beetles (Coleoptera), Opiliones and Anisolabididae (Dermaptera), collected with the potential to be used as biocontrol agents against P. japonica in future Integrated Pest Management programmes. A thorough sampling programme was conducted in maize and pasture fields in two Islands of the Azores (São Miguel and São Jorge) in the summer of 2022.

The whitefly, Bemisia tabaci (Gennadius) cryptic species Mediterranean (MED), is a destructive insect pest worldwide. In order to contribute to controlling B. tabaci by non-chemical methods, we examined the possibility of using a combination of trap/barrier crops and a parasitoid natural enemy in cotton. We performed field experiments using cantaloupe (Cucumis melo) and sunflower (Helianthus annuus) as trap crops and maize (Zea mays) as a barrier crop combined with periodic releases of the parasitoid Eretmocerus hayati in Hebei Province, Northern China. All treatments significantly reduced immature whitefly densities. Parasitism rate was significantly higher in cotton plots intercropped with sunflower and with perimeter-planted cantaloupe. Adult whitefly density was negatively related to parasitoid abundance and was significantly lower in cotton plots intercropped with maize than in the control plots. Intercropping was more effective than perimeter-planting at reducing B. tabaci densities and increasing yield. Parasitoid dispersal was not hampered by barrier crops, indicating that the two methods of control are compatible. These results contribute to the development of integrated pest management methods against this important pest.

Late wilt disease (LWD), caused by Magnaporthiopsis maydis, represents a major constraint to maize production in drought-affected regions. Conventional management strategies, including the use of resistant cultivars and chemical fungicides, often fail due to the high adaptability of the pathogen, environmental limitations, and economic constraints. This thesis investigated the potential of bacterial biocontrol agents (BCAs) as sustainable tools to mitigate LWD through mechanisms of nutrient competition, drought tolerance, and induced resistance. Sixty-two bacterial strains were isolated from infected maize fields, several of which mainly belonging to the genus Pseudomonas displayed strong antagonistic activity against M. maydis. Biochemical and metabolic analyses revealed that pathogen suppression was associated with oxidative stress regulation and competition for essential nutrients such as phosphorus, potassium, and iron. Growth-shelf experiments demonstrated that bacterial inoculation enhanced plant growth, antioxidant capacity, and lipid homeostasis, while reducing fungal colonization. Under drought stress, disease severity increased markedly; however, drought-tolerant BCAs improved maize performance through osmolyte accumulation, nutrient balance, and increased physiological resilience, whereas azoxystrobin showed limited protection. For the first time, this work also emphasized the importance of early infection detection to optimize integrated management strategies, which were addressed through nutrient profiling and physiological and biochemical analyses performed in 23-day-old maize plants, prior to the appearance of visible symptoms. Overall, the findings highlight the multifaceted role of BCAs in mitigating M. maydis infection and drought stress, contributing to the development of climate-resilient and sustainable disease management approaches for maize production systems.

A multi-analyte method for identification and quantification of 23 regulated and emerging mycotoxins was devel- oped in maize samples by ultra high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Several extraction methodologies were evaluated, including solid-liquid extraction (SLE), solid- phase extraction (SPE), and modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) protocols. The final method consisting of an extraction by QuEChERS using C18 sorbents, was in-house validated in terms of linearity, repeatability, reproducibility, recovery, Limits of Detection (LOD) and Limits of Quantification (LOQ). Acceptable performance characteristics were obtained according to specific and general European regulations for regulated and emerging mycotoxins, respectively. The developed method proved to be specific and selective for all mycotoxins, with LODs and LOQs lower than 21.10 and 37.49 ng g − 1 , respectively; and recoveries ranging from 55.25 to 129.48% with precisions, expressed as relative standard deviations, below 15.03%. The method was successfully applied to real maize samples.