Coffea canephora has two botanical varieties, Robusta and Conilon. Intraspecific variability was hypothesized and projected for the selection of C. canephora plants able to maintain production in the context of global climate changes. For that, architectural, C-assimilation and biomass analyses were performed on 17-month-old Robusta (clones ‘A1’ and ‘3 V’) and Conilon (clones ‘14’ and ‘19’) varieties grown in non-limiting soil, water, and mineral nutrient conditions. Nondestructive coffee plant architecture coding, reconstruction, and plant photosynthesis estimations were performed using a functional-structural plant modeling platform OpenAlea. 3D reconstructions and inclusion of parameters calculated and estimated from light response curves, such as dark respiration (R_d), maximum rate of carboxylation of RuBisCO, and photosynthetic electron transport allowed the estimation of instantaneous and daily plant photosynthesis. The virtual orchard leaf area index was low, and light was not a limiting factor in early C. canephora development stages. Under such conditions, Robusta assimilated more CO₂ at the plant and orchard scale and produced higher total biomass than Conilon. Lower plant daily photosynthesis and total biomass were correlated to higher R_d in Conilon than in Robusta. Among the architectural traits, leaf inclination, size, and allometry were most highly correlated with plant assimilation and biomass. Relative allocation in leaf biomass was higher in ‘19’ Conilon than in young Robusta plants, indicating intraspecific biomass partitioning. Similarly, variation in relative distribution of the root biomass and the root volume reflected clonal variation in soil occupation, indicating intraspecific variability in space occupation competitiveness. C. canephora denoted high root allocation in both Conilon and Robusta clones. However, relevant differences at sub-specific levels were found, indicating the high potential of C. canephora to cope with drought events, which are expected to occur more frequently in the future, due to climate changes. The methodology developed here has the potential to be used for other crops and tree species.

Coffea canephora genotypes adopt distinct strategies to cope with drought and rehydration. We hypothesized that the greater drought tolerance of genotype ‘3V’ compared to ‘A1’, previously reflected in physiological and anatomical leaf traits after two water-stress (WS) cycles, could also be observed in P–V curve responses, root and branch anatomy, leaf midrib elongation (CVL), and root distribution. The ‘3V’ and ‘A1’ plants were grown under well-watered (WW) conditions and two cycles of water stress (WS). The ‘3V’ was more sensitive to WS, with reduced branch xylem vessel density (BXVD), while ‘A1’ demonstrated increased BXVD. Root xylem vessel area (RXVA) decreased to a greater extent in ‘3V’ than in ‘A1’, and both genotypes showed increased bulk elastic modulus. Regardless of water conditions, ‘A1’ maintained a higher relative leaf water content at the turgor loss point (RWC_TLP). Morphological acclimation did not occur in the second WS cycle. The ‘3V’ plants developed greater root mass in deeper soil layers than ‘A1’ under the WS condition. These findings suggest that ‘A1’ follows a conservative drought-avoidance strategy with lower physio-morphological plasticity, while ‘3V’ exhibits greater drought tolerance. Such responses highlighted coordinated physiological, morphological, and anatomical adaptations of the above- and below-ground organs for resource acquisition and conservation under WS.

Understanding the dynamics of physiological changes involved in the acclimation responses of plants after their exposure to repeated cycles of water stress is crucial to selecting resilient genotypes for regions with recurrent drought episodes. Under such background, we tried to respond to questions as: (1) Are there differences in the stomatal-related and non-stomatal responses during water stress cycles in different clones of Coffea canephora Pierre ex A. Froehner? (2) Do these C. canephora clones show a different response in each of the two sequential water stress events? (3) Is one previous drought stress event sufficient to induce a kind of “memory” in C. canephora? Seven-month-old plants of two clones (’3V’ and ‘A1’, previously characterized as deeper and lesser deep root growth, respectively) were maintained well-watered (WW) or fully withholding the irrigation, inducing soil water stress (WS) until the soil matric water potential (Ψ_msoil) reached ≅ −0.5 MPa (−500 kPa) at a soil depth of 500 mm. Two sequential drought events (drought-1 and drought-2) attained this Ψ_msoil after 19 days and were followed by soil rewatering until a complete recovery of leaf net CO₂ assimilation rate (A_net) during the recovery-1 and recovery-2 events. The leaf gas exchange, chlorophyll a fluorescence, and leaf reflectance parameters were measured in six-day frequency, while the leaf anatomy was examined only at the end of the second drought cycle. In both drought events, the WS plants showed reduction in stomatal conductance and leaf transpiration. The reduction in internal CO₂ diffusion was observed in the second drought cycle, expressed by increased thickness of spongy parenchyma in both clones. Those stomatal and anatomical traits impacted decreasing the A_net in both drought events. The ‘3V’ was less influenced by water stress than the ‘A1’ genotype in A_net, effective quantum yield in PSII photochemistry, photochemical quenching, linear electron transport rate, and photochemical reflectance index during the drought-1, but during the drought-2 event such an advantage disappeared. Such physiological genotype differences were supported by the medium xylem vessel area diminished only in ‘3V’ under WS. In both drought cycles, the recovery of all observed stomatal and non-stomatal responses was usually complete after 12 days of rewatering. The absence of photochemical impacts, namely in the maximum quantum yield of primary photochemical reactions, photosynthetic performance index, and density of reaction centers capable of Q_A reduction during the drought-2 event, might result from an acclimation response of the clones to WS. In the second drought cycle, the plants showed some improved responses to stress, suggesting “memory” effects as drought acclimation at a recurrent drought.

MÉTODOS DE ESTIMATIVA DA EVAPOTRANSPIRAÇÃO DE REFERÊNCIA (ET₀) NO MUNICÍPIO DE SANTA TERESA, ES     ANDRE DALLA BERNARDINA GARCIA¹; JOSÉ CARLOS MENDONÇA²  E CLAUDIO MARTINS DE ALMEIDA^{3 1}Instituto Federal do Espírito Santo, Rodovia ES 080, Km 93, São João de Petrópolis, CEP 29660-000, Santa Teresa, ES, Fone:(27)3259-7878, E-mail:andredallabg@outlook.com ²Laboratório de Engenharia Agrícola/UENF, Av. Alberto Lamego, 2000,P1,sl 209, Horto, Campos dos Goytacazes, RJ, Fone (22) 2739-7308, E-mail: mendonca@uenf.br ³Laboratório de Engenharia Agrícola/UENF, Av. Alberto Lamego, 2000,P1,sl 209, Horto, Campos dos Goytacazes, RJ, Fone (22) 2739-7308, E-mail: claudio@pq.uenf.br                                                                  1 RESUMO                                                                             Devido aos constantes debates ocorridos sobre a racionalização dos recursos hídricos, a busca de maneiras e boas práticas de utilização da água têm sido cada vez mais difundidas, principalmente na agricultura. Dentre os meios de preservar os recursos hídricos está o manejo de irrigação, por isso é muito importante realizar a estimativa da evapotranspiração de referência (ET₀). Neste contexto, o presente trabalho foi desenvolvido para o município de Santa Teresa, localizado na meso região Central Espírito-Santense com o objetivo de avaliar e comparar diferentes métodos de estimativa da ET₀ com o método de Penman-Monteith FAO56, considerado como padrão de calibração, na ausência de dados lisimétricos. Os métodos utilizados foram os de Hargreaves-Samani, Radiação Solar, Makkink, Jesen-Haise, Linacre e Penman Simplificado. O coeficiente de determinação (R²), índice de concordância de Willmott (D), o erro médio absoluto (MAE), o erro máximo (EMAX), a eficiência do método (EF) e o índice de desempenho (c) foram utilizados para avaliar os indicadores observados. Dentre os métodos avaliados, os que apresentaram melhores resultados foram os de Makkink e Penman Simplificado (R² = 0,96 e 0,96; D= 0,99 e 0,97; MAE = 0,23 e 0,44; EMAX = 1,36 e 1,07; EF = 0,95 e 0,87 e c = 0,97 e 0,95) respectivamente, seguidos do método de Hargreaves-Samani (R² = 0,86; D= 0,91; MAE = 0,60; EMAX = 2,16; EF = 0,69 e c = 0,85). Os resultados obtidos com os métodos de Linacre, Radiação Solar e Jensen-Haise foram inferiores e sendo a sua utilização não recomendada para a região de Santa Teresa, ES.   Palavras-chave: Agrometeorologia, demanda hídrica, irrigação, Penman-Monteith GARCIA, A. D. B.; MENDONÇA, J. C.; MARTINS, C. A. METHODS FOR ESTIMATING REFERENCE EVAPOTRANSPIRATION (ET₀) FOR THE CITY OF SANTA TERESA, ES     2 ABSTRACT   Due to constant discussion about rationalization of water resources, the search for ways and good practices in water use have been increasingly widespread, especially in agriculture. Among the means of preserving water resources is irrigation management, so it is very important to estimate the reference evapotranspiration (ET₀). In this context, the present work was developed for the municipality of Santa Teresa, located in Central Espírito-Santo mesoregion with the objective of evaluating and comparing different ET₀ estimation methods with Penman-Monteith FAO56 method considered as calibration standard, in the absence of lysimetric data. The methods used were those of Hargreaves-Samani, Solar Radiation, Makkink, Jesen-Haise, Linacre and Penman Simplified. The coefficient of determination (R²), Willmott concordance index (D), mean absolute error (MAE), maximum error (EMAX), method efficiency (EF) and performance index (c) were used for assessing the observed indicators. Among the evaluated methods, the ones with the best results were Makkink and Penman Simplified (R² = 0.96 and 0.96 D = 0.99 and 0.97, MAE = 0.23 and 0.44, EMAX = 1.36 and 1.07, EF = .95 and 0.87 and c = 0.97 and 0.95) respectively, followed by Hargreaves-Samani methods (R² = 0.86, D = 0.91, MAE = 0.60, EMAX = 2.16, EF = 0.69 and c = 0.85). The results obtained with the methods of Linacre, Solar Radiation and Jensen-Haise were lower and their use is not recommended for the region of Santa Teresa, ES. Keywords: Agrometeorology, hydric demand, irrigation, Penman-Montheith  

O café tem grande importância econômica na agricultura brasileira, sendo o segundo maior produtor mundial, atrás apenas da Etiópia. Entretanto, para exportação cada vez mais é requerido alta qualidade e seletividade dos grãos, para que tenham um processamento adequado nas indústrias. O objetivo do presente trabalho foi avaliar os efeitos da aplicação de diferentes condições de irrigação na uniformidade e classes de peneira dos grãos moca do café conilon. O experimento foi conduzido na área pertencente à Universidade Estadual do Norte Fluminense. O delineamento experimental utilizado foi de blocos casualizados, com quatro repetições, composto pelos fatores: Sistema de irrigação (superficial e subsuperficial) e Lâminas de água (0, 25, 50, 100 e 125% da ET0), estas se constituíram nos tratamentos. A classificação por peneiras foi determinada segundo o formato do grão e sua granulometria, e diferentes números de peneiras, sendo definidos como Moca Graúdo (MG), Moca Médio (MD), Moca Miúdo (MM). Após realização do estudo concluiu-se que há tendência na uniformização da produção nas peneiras 10 a 11, classificados como Moca Médio com o aumento da irrigação, para as condições apresentadas, de modo que as lâminas de 100 a 125% da ET0 tiveram o maior percentual para essa classe de grãos.

As Ciências Agrárias possuem alguns dos campos mais promissores da atualidade, principalmente em termos de avanços científicos e tecnológicos. Contudo, um dos grandes desafios, é a utilização dos recursos naturais de forma sustentável, maximizando a excelência e a produtividade no setor agropecuário e agroindustrial, atendendo a demanda cada vez mais exigente do mercado consumidor. Neste contexto, a obra “Impacto, Excelência e Produtividade das Ciências Agrárias no Brasil” em seus volumes 3 e 4, compreendem respectivamente 22 e 22 capítulos, que possibilitam ao leitor ampliar o conhecimento sobre temas atuais e de expressiva importância nas Ciências Agrárias. Ambos os volumes, apresentam trabalhos que contemplam questões agropecuárias, de tecnologia agrícola e segurança alimentar. Na primeira parte, são apresentados estudos relacionados à fertilidade do solo, desempenho agronômico de plantas, controle de pragas, processos agroindustriais, e bem estar animal, entre outros assuntos. Na segunda parte, são abordados trabalhos envolvendo análise de imagens aéreas e de satélite para mapeamentos ambientais e gerenciamento de dados agrícolas e territoriais. Na terceira e última parte, são apresentados estudos acerca da produção, caracterização físico-química e microbiológica de alimentos, conservação pós-colheita, e controle da qualidade de produtos alimentares. O organizador e a Atena Editora agradecem aos autores e instituições envolvidas nos trabalhos que compõe a presente obra. Por fim, desejamos que este livro possa favorecer reflexões significativas acerca dos avanços científicos nas Ciências Agrárias, contribuindo para novas pesquisas no âmbito da sustentabilidade que possam solucionar os mais diversos problemas que envolvem esta grande área. Júlio César Ribeiro