O objetivo do trabalho foi quantificar a influência de variáveis ambientais sobre a interação genótipos x ambientes em meloeiro. Foram utilizados dados de produtividade de oito híbridos de melão Cantaloupe testados em nove ambientes no Estado do Rio Grande do Norte. Para a identificação das variáveis ambientais relacionadas à interação G x A e sensibilidade dos híbridos, estimaram-se modelos de regressão fatorial, coeficiente de correlação de Spearman entre os escores dos componentes principais da análise AMMI e as médias das variáveis ambientais. As temperaturas média, máxima e mínima são as que mais influenciam na interação genótipos x ambientes em meloeiro para a produtividade.

A distribuição natural dos teores de elementos-traço nos solos é muito variável. Assim, o estabelecimento de valores de referência de qualidade (VRQs) a partir das médias ou dos intervalos globais de concentração dos elementos, muitas vezes, é pouco adequado. Por essa razão, propôs-se estabelecer os VRQs para elementos-traço no Estado do Espírito Santo, a partir de grupos de solos obtidos com base em atributos físicos e químicos. Foram utilizadas a análise de correlação de Pearson, a análise fatorial com extração dos fatores em componentes principais (AF), a análise de agrupamento hierárquico (AAH) e a análise discriminante (AD). A análise da correlação de Pearson e a análise fatorial revelaram que as variáveis Fe, Mn, Ti, silte+argila e carbono orgânico (CO) são atributos de solo importantes para a distribuição dos elementos-traço nos solos estudados. O uso da análise de agrupamento possibilitou a formação de quatro grupos de solo e diminuiu a variabilidade dos teores de elementos-traço nos solos pela formação de grupos mais homogêneos, além de evidenciar a relação dos diferentes solos em um mesmo grupo com a pedologia e o material de origem. Os VRQs determinados a partir dos grupos de solo, em geral, apresentaram valores inferiores, bem como menor amplitude, entre os percentis 90 e 75, em relação aos obtidos quando se utilizou o universo amostral.

The canonical correlation is used to correlate groups of distinct variables. The objective of this study was to use canonical correlation analysis to evaluate the interaction between water quality attributes clogging-causing and the hydraulic performance of non-pressure compensating drippers operating with dilutions of aquaculture effluent in well water. The experiment was in a completely randomized design in a split-split-plot scheme with three replicates, with five dilutions in the plots (Dilution 1: 100% aquaculture effluent; Dilution 2: 75% aquaculture effluent + 25% well water; Dilution 3: 50% aquaculture effluent + 50% well water; Dilution 4: 25% aquaculture effluent + 75% well water; and Dilution 5: 100% well water), three emitters in the sub-plots (ST (1.6 L h^-1), SL (1.6 L h^-1) and NJ (1.7 L h^-1)), and three operating times in the sub-subplots (0, 80 and 160 hours, in which 0 hours operating time means the start of evaluations). The statistical analyses performed were correlation matrix and canonical analysis. The canonical correlation analysis indicated that when the concentrations of attributes increase, the hydraulic performance of the drippers decreases. The interaction of this group of attributes indicates that the clogging of drippers operating with the five dilutions of aquaculture effluent in well water occurs by the combined action of physical, chemical, and biological agents. The ST dripper was the least sensitive to the group of quality attributes of the dilutions, whereas the most sensitive was the SL dripper.

Melon (Cucumis melo L.) is cultivated worldwide, with prominence in the Northeast region of Brazil, due to its favorable soil and climate conditions. However, over the years, the genotype × environment (GxE) interaction phenomenon has been occurred, which can complicate the selection process depending on its extent (whether it is a simple or complex interaction). In this context, melon breeding programs aim to identify adaptable and stable genotypes, capable of reaching their maximum potential. Therefore, the objectives of this study were to investigate GxE interactions and identify cultivars with greater adaptability and phenotypic stability using various methods for comparison. Thirteen melon hybrids were assessed in four municipalities in the state of Rio Grande do Norte, across two planting dates, totaling eight distinct environments. The experiments were conducted in randomized complete blocks with three replications. The traits evaluated included the number of fruits per plant and total soluble solids. Several adaptability and stability methods were employed and compared including Wricke, Eberhart and Russell, Lin and Binns, Annicchiarico, GGE Biplot, and Resende (harmonic mean of relative performance of genotypic values). Significant GxE interaction for the number of fruits per plant was found to be simple, whereas for soluble solids, it was crossed. The methods of Linn and Binns, Annicchiarico, and Resende showed strong correlations among them and were all correlated with the trait mean. The HA-08 hybrid emerged as the most promising, exhibiting high number of fruits per plant, high soluble solids content, and exceptional adaptability and stability.

Clogging is a major constraint to the agricultural reuse of produced water; however, ultra-low-frequency dynamic electronic pulses (EPs) can help control biofouling in drip emitters. This study aimed to evaluate the reduction in clogging in non-self-compensating emitters applying onshore oil-and-gas-produced water treated with EP. Three experimental benches were assembled using drip irrigation units supplied with different water sources: water supply (WS), produced water with EP (OPW + EP), and produced water without treatment (OPW). Hydraulic performance was monitored every 40 h for 400 h using average flow rate variation (AFVR), flow variation coefficient (FVC), and distribution uniformity (UD) indices. Data were analyzed using RT-1 analysis with Bonferroni post hoc tests. Results showed that the interaction between water sources and evaluation times significantly (p ≤ 0.01) affected the hydraulic indices. After 400 h, the indices ranked as UD and FVC: WS > OPW + EP > OPW, and AFVR: OPW + EP = WS > OPW. Although OPW presented a low risk of clogging, the application of EP mitigated the obstruction and maintained higher uniformity by reducing clogging. These findings demonstrate that ultra-low-frequency electronic pulses are an innovative anti-clogging technology and provide insights for the sustainable application of produced water.