ABSTRACT: The study of genotypic relationships between drought tolerance indices and agronomic traits of interest in wheat breeding is useful for designing selection strategies. The objective of this research was to investigate the cause-and-effect relationships between agronomic traits and drought tolerance indices through the analysis of canonical correlations. Two trials (control and stress) were conducted in winter 2020 in Viçosa, MG, Brazil. The traits evaluated were: (days for heading, plant height, mass and number of grains per spike, mass of one hundred grains, and grain yield). Grain yield data from the control and stress conditions were used to construct five drought tolerance indices. The data were subjected to mixed model analysis for estimation of genetic parameters and prediction of genotypic values (REML/BLUP), and then the genotypic values were used to calculate the correlation coefficients between the traits. Two groups of traits were established for the study of canonical correlations, the first group consisting of agronomic traits and the second by drought tolerance indices. There was a significant genotype effect for all evaluated traits. The canonical pairs were significant, which indicated the existence of dependence between the groups. Days to heading trait can be used in the indirect selection of wheat genotypes for drought tolerance. ABSTRACT strategies causeandeffect cause correlations 202 Viçosa MG Brazil days height spike yield. . yield) REML/BLUP, REMLBLUP REML/BLUP , REML BLUP (REML/BLUP) 20 (REML/BLUP 2

RESUMO: O estudo das relações genotípicas entre índices de tolerância à seca e caracteres agronômicos de interesse no melhoramento de trigo é útil para traçar estratégias de seleção. Objetivou-se com este trabalho investigar as relações de causa e efeito entre características agronômicas e índices de tolerância à seca via análise de correlações canônicas. Dois ensaios (controle e estresse) foram conduzidos no inverno de 2020 em Viçosa, MG, Brasil. Foram avaliados os caracteres (dias para o espigamento, altura da planta, massa e número de grãos por espiga, massa de cem grãos e rendimento de grãos). Os dados de produtividade dos ensaios de controle e estresse foram utilizados para construir cinco índices de tolerância à seca. Os dados foram submetidos à análise de modelos mistos para estimação dos parâmetros genéticos e predição dos valores genotípicos (REML/BLUP), em seguida, os valores genotípicos foram utilizados para calcular os coeficientes de correlação entre os caracteres. Dois grupos de caracteres foram estabelecidos para o estudo das correlações canônicas, sendo o primeiro grupo constituído pelas variáveis agronômicas e o segundo pelos índices de tolerância à seca. Houve efeito significativo de genótipo para todas as características avaliadas. Os pares canônicos foram significativos, o que indicou a existência de dependência entre os grupos. O caráter dias para o espigamento pode ser utilizado na seleção indireta de genótipos de trigo para tolerância à seca. RESUMO Objetivouse Objetivou se canônicas 202 Viçosa MG Brasil planta espiga grãos. . grãos) REML/BLUP, REMLBLUP REML/BLUP , REML BLUP (REML/BLUP) seguida avaliadas significativos 20 (REML/BLUP 2

ABSTRACT The cowpea is a legume that is widely grown in the north-east of Brazil, and which has been gaining ground in other regions of the country. The main producer is the state of Ceará, with a large planted-area, albeit low productivity due to a lack of producer technology and adapted cultivars. The aim of this study was to identify and recommend superior genotypes in terms of adaptability and stability under rainfed and irrigated conditions, in addition to genotypes with reduced grain darkening. To this end, six experiments were conducted in different districts of Ceará (Crato, Pentecoste, Crateús, Madalena, Bela Cruz and Limoeiro do Norte) and one laboratory experiment, to evaluate grain darkening. The experimental design of the field trials was of randomised blocks, with 14 genotypes and 4 replications. The analysis of variance showed a significant effect from the genotypes and environments and their interaction, so GGE Biplot analysis was carried out to evaluate adaptability and stability. To evaluate grain darkening, a completely randomised design was used in a simple factorial scheme with six previously selected genotypes and five different storage times (0, 2, 4, 6 and 8 months). There was a significant effect from the genotypes and storage time. Genotype 1 showed the least darkening, and can be recommended for environments to which it is best adapted (Crato and Crateús). Genotype 9 was considered the most stable for grain yield, and can be more broadly recommended for the semi-arid region of the state of Ceará. northeast north east Brazil country plantedarea, plantedarea planted area, area planted-area cultivars conditions darkening end Crato, Crato Pentecoste Crateús Madalena Norte experiment blocks replications interaction 0, 0 (0 2 months. months . months) time Crateús. Crateús) yield semiarid semi arid (

ABSTRACT: Plants’ physiology changes through the day because photoassimilates can increase water-soluble carbohydrate concentration in the afternoon compared to the morning. This study evaluated the harvest time effect on whole-plant corn silage morphological composition, particle size, fermentation profile, chemical composition, in vitro degradation, and estimated milk yield. A two-year agronomic assay was performed in a completely random design, and one experimental silo was produced by each parcel (n = 16). The afternoon harvest increased (P < 0.01) dry matter content compared to the morning harvest. Harvest time did not affect (P ≥ 0.32) corn grain, stalk, leaf proportion, and silage particle size. However, the morning harvest increased dry matter recovery (P = 0.01) and had no effect (P ≥ 0.10) on silage pH and concentrations of lactic and acetic acid compared to the afternoon harvest. In addition, afternoon harvest instead of morning harvest increased (P ≤ 0.05) silage starch, water-soluble carbohydrates, acid detergent lignin, and ether extract content and dry matter in vitro degradation. Controversially, treatments showed no effect (P ≥ 0.14) on silage energy concentration, estimated energy content, and milk yield. Thus, the morning harvest produces more silage dry matter, but the afternoon harvest improves corn silage’s nutritional value with no impact on estimated milk yield. ABSTRACT Plants watersoluble water soluble wholeplant whole plant composition size profile degradation yield twoyear two year design n 16. 16 . 16) P 0.01 001 0 01 0.32 032 32 grain stalk proportion However 0.10 010 10 addition 0.05 005 05 starch carbohydrates lignin Controversially 0.14 014 14 Thus silages s 1 0.0 00 0.3 03 3 0.1 0.

RESUMO: A fisiologia das plantas muda ao longo do dia porque os fotoassimilados podem aumentar a concentração de carboidratos solúveis em água à tarde em comparação com a manhã. Este estudo teve como objetivo avaliar o efeito do horário de colheita na composição morfológica da silagem de milho de planta inteira, tamanho de partícula, perfil de fermentação, composição química, degradação in vitro e estimativa da produção de leite. Um ensaio agronômico de dois anos foi realizado em delineamento inteiramente casualizado, e um silo experimental foi produzido por cada parcela (n = 16). A colheita da tarde aumentou (P < 0,01) o teor de matéria seca em relação à colheita da manhã. A época de colheita não afetou (P ≥ 0,32) a proporção de grãos, colmos e folhas do milho e o tamanho das partículas da silagem. Entretanto, a colheita da manhã aumentou (P = 0,01) a recuperação de matéria seca e não teve efeito (P ≥ 0,10) no pH da silagem e nas concentrações de ácido láctico e acético em comparação à colheita da tarde. Além disso, a colheita da tarde, em vez da colheita da manhã, aumentou (P ≤ 0,05) o amido da silagem, os carboidratos solúveis em água, a lignina detergente ácida e o teor de extrato etéreo e a degradação in vitro da matéria seca. Controversamente, os tratamentos não mostraram efeito (P ≥ 0,14) na concentração de energia da silagem, no conteúdo energético estimado e na produção de leite. Assim, a colheita da manhã produz mais matéria seca da silagem, mas a colheita da tarde melhora o valor nutricional da silagem de milho sem impacto na produção estimada de leite. RESUMO inteira partícula fermentação química leite casualizado n 16. 16 . 16) P 0,01 001 0 01 0,32 032 32 grãos Entretanto 0,10 010 10 disso 0,05 005 05 Controversamente 0,14 014 14 Assim 1 0,0 00 0,3 03 3 0,1 0,

ABSTRACT Soil water balance models can be a good option for studying crop growth and yield responses under different water supply levels. The aim of this study was to evaluate the effect of different irrigation strategies on sunflower yield and water productivity using field experiments and soil water balance simulations. Two field experiments were performed. In 2018/19, four irrigation strategies (aimed at maintaining soil available water at 80, 70, 60, and 50% of total available water) were evaluated. In 2020/21 an irrigated and a rain-fed treatment were evaluated. The SIMDualKc model was calibrated and validated to simulate soil water balance and derive the dual coefficients using plant variables from field observations. Grain yield was highest in the treatment maintained at 70% of total available water in Study I, suggesting that a water replenishment reduction strategy may be an alternative to irrigation management, especially in locations where water is scarce. The statistical indicators showed good performance of the model in simulating the water available in the soil, with the coefficient of determination > 0.90 and modeling efficiency above 0.86 for all cases. The study allowed the calibration of the single and basal crop coefficients of sunflower, which are important parameters for irrigation management. levels simulations performed 201819 2018 19 2018/19 aimed 80 70 60 50 evaluated 202021 2020 21 2020/2 rainfed rain fed observations I management scarce 090 0 90 0.9 086 86 0.8 cases 20181 201 1 2018/1 8 7 6 5 20202 202 2 2020/ 09 9 0. 08 20 2018/

RESUMO Os modelos de balanço hídrico do solo podem ser uma boa opção para estudar o crescimento das culturas e as respostas de rendimento sob diferentes níveis de fornecimento de água. O objetivo deste estudo foi avaliar os efeitos de diferentes estratégias de irrigação na produtividade do girassol e na produtividade da água usando experimentos de campo e simulações de balanço hídrico do solo. Dois experimentos de campo foram realizados. Em 2018/19, foram utilizadas quatro estratégias de irrigação (mantida a água disponível no solo em 80, 70, 60 e 50% da água total disponível). Em 2020/21 foi utilizado um tratamento irrigado e de sequeiro. O modelo SIMDualKc foi calibrado e validado para simular o balanço hídrico do solo e derivar os coeficientes duais usando variáveis da planta a partir de observações de campo. A produtividade de grãos foi maior no tratamento mantido a 70% do total de água disponível no Estudo I, sugerindo que a redução da reposição de água pode ser uma alternativa para o manejo da irrigação, principalmente em locais onde a água é escassa. Os indicadores estatísticos mostraram um bom desempenho do modelo na simulação da água disponível no solo, com coeficiente de determinação > 0,90 e eficiência de modelagem acima de 0,86 para todos os casos. O estudo permitiu a calibração do coeficiente de cultura simples e basal do girassol, que são parâmetros importantes para o manejo da irrigação. realizados 201819 2018 19 2018/19 mantida 80 70 6 50 disponível. . disponível) 202021 2020 21 2020/2 sequeiro I escassa 090 0 90 0,9 086 86 0,8 casos 20181 201 1 2018/1 8 7 5 20202 202 2 2020/ 09 9 0, 08 20 2018/

ABSTRACT: The study of adaptability, stability, and productivity is essential for selecting and recommending superior genotypes. This fact is particularly the case for the introduction of common bean cultivars in Rio de Janeiro, Brazil, whose production is negligible and does not meet the internal demand. Thus, this study estimated genetic parameters and selection gains and undertake a simultaneous selection for adaptability, stability, and productivity in black bean genotypes via mixed models. The investigation was carried out in three municipalities in the state of Rio de Janeiro during three crop years. The trials were set up in a randomized block design with 11 genotypes and three replications. High mean heritability (81%) and selection accuracy (90%), as well as good selection prospects, were observed. Gains between 1.03 and 9.49% were achieved for grain yield. Simultaneous selection was efficient, indicating two black bean lines (CNFP 15290 and CNFP 15361) as the most productive, adaptable, and stable. As such, these lines have the potential to be released as new black bean cultivars for the state of Rio de Janeiro. ABSTRACT adaptability stability Brazil demand Thus models years 1 replications 81% 81 (81% 90%, 90 90% , (90%) prospects observed 103 03 1.0 949 9 49 9.49 yield efficient 1529 15361 productive adaptable stable such 8 (81 (90% 10 0 1. 94 4 9.4 152 1536 (8 (90 9. 15 153 ( (9

RESUMO: O estudo de adaptabilidade, estabilidade e produtividade é importante para selecionar e recomendar genótipos superiores. Esse fato é particularmente válido para a introdução de cultivares de feijão comum no Rio de Janeiro, Brasil, cuja produção é ínfima e não atende a demanda interna. Assim, este trabalho teve como objetivo estimar parâmetros genéticos e ganhos de seleção e realizar uma seleção simultânea para adaptabilidade, estabilidade e produtividade de genótipos de feijão preto através de modelos mistos. O estudo foi realizado em três municípios do estado do Rio de Janeiro e em três anos agrícolas. Os ensaios foram instalados em delineamento de blocos casualizados com 11 genótipos e três repetições. Observou-se alta herdabilidade média (81%), acurácia seletiva (90%) e boas perspectivas de seleção. Também foram observados ganhos satisfatórios para a característica entre 1,03 e 9,49%. A seleção simultânea foi eficiente e permitiu selecionar duas linhagens de feijão preto CNFP (15290 e 15361) como sendo as mais produtivas, adaptáveis e estáveis e, portanto, têm potencial para serem lançadas como novas cultivares de feijão preto para o estado do Rio de Janeiro. RESUMO adaptabilidade superiores Brasil interna Assim mistos agrícolas 1 repetições Observouse Observou se 81%, 81 81% , (81%) 90% 90 (90% 103 03 1,0 949 9 49 9,49% 15290 (1529 15361 produtivas portanto 8 (81% (90 10 0 1, 94 4 9,49 1529 (152 1536 (81 (9 9,4 152 (15 153 (8 ( 9, 15 (1

ABSTRACT Plant growth regulators play an essential role in plants’ biochemical processes. In this study, foliar spray was applied using three growth regulators, gibberellic acid (GA3), naphthalene acetic acid (NAA), and 6-benzyl amino purine (BAP), to investigate their effects on wheat (Triticum aestivum L.) ‘Giza-171’ yield traits and grain biochemical constituents, including sugars, carbohydrates and protein. The assessed growth regulators (GA3, NAA, and BAP) were applied at 100 and 150 mg L-1 concentrations. The results indicated significant improvements in wheat grain yield and 1000-grain weight, which increased by 15.40% and 24.78%, respectively, using GA3 at 150 and 100 mg L-1. In addition, the highest contents of protein and carbohydrates were observed with samples treated by the foliar application of NAA at 150 mg L-1 and BAP at 100 mg L-1, respectively. The fat content in wheat grains increased by 1.97% and 2.73% with foliar spray with 150 mg L-1 NAA and 100 mg L-1 BAP, respectively. The lipid profile showed cis-linoleic acid was the primary fatty acid, followed by palmitic acid; the content of linoleic acid slightly increased with GA3 treatment to 50.42%, while palmitic acid significantly increased with 100 mg L-1 NAA. The total saturated and unsaturated fatty acids recorded 33.64% and 66.30%, respectively; the 150 mg L-1 NAA treatment had the lowest saturated fatty acid content. The SDS-PAGE profiles showed that growth regulators significantly enhanced the wheat protein where new bands appeared, especially in 100 mg L-1 GA3 and 100 mg L-1 BAP treatments. The applied growth regulators improved wheat yield, contents of some compounds, and nutritional value.

ABSTRACT The ‘RD6’ glutinous rice (Oryza sativa L.), developed from the popular aromatic rice ‘KDML105’ through gamma irradiation, is a key economic cultivar widely consumed in Thailand and exported throughout Asia. However, cultivation of the ‘RD6’ faces challenges due to its low grain yield and growth performance. The objective of this study was to use biostimulant chitosan and brassinosteroids to promote growth performance, nutrition, and yield of the ‘RD6’ rice. Chitosan (2.5, 5.0, 7.5, and 10.0 mg L-1) and brassinosteroids (0.00005, 0.0005, 0.001, and 0.002 mg L-1) were sprayed twice at 40- and 75-d-old rice plants in paddy fields. The results demonstrated that foliar spraying with 7.5 mg L-1 chitosan can promote leaf growth of ‘RD6’ and improve grain yield by 24% as compared with the control. More pronounced effects were observed with 0.002 mg L-1 brassinosteroid, improving not only growth but also ‘RD6’ yield by 41.8% compared to the control. Moreover, 0.002 mg L-1 brassinosteroids can enhance antioxidant capacities (total phenolic contents), elemental K and Ca contents, and the aroma compound 2-acetyl-1-pyrroline (2AP) contents in the rice grains. Furthermore, the use of 0.002 mg L-1 brassinosteroids proved to be a financially sound investment, yielding superior net returns and an advantageous benefit-cost ratio compared with 7.5 mg L-1 chitosan. Therefore, the use of exogenous brassinosteroids on glutinous rice in this study offers promising advantages for promoting the growth and physiological performance of rice plants.

ABSTRACT Potassium (K) and B are important for phloem translocation, reproductive growth, and grain formation. A 2-yr field study was conducted to evaluate the effect of K and B applied through the soil and foliar application on sunflower (Helianthus annuus L.) Experiments included the soil application of K (62 kg ha-1) and B (5 kg ha-1) and foliar spray of K (1%) and B (0.1%). Furthermore, the soil-applied K and B was supplemented with three foliar sprays of either K, B, or both at 45, 60 and 75 d after sowing. The results revealed that K and B fertilization improved the agronomic parameters of sunflower, including plant height, head diameter, achenes per head, achene weight, yield, seed oil contents and oil quality. The soil applied K at 62 kg ha-1 followed by foliar spray of 1% K + 0.1% B at 45, 60 and 75 DAS resulted in production of taller plants (192 and 172 cm), head diameter (23 and 28 cm), achene per head (954 and 1063), 1000 achene weight (68 and 67.58 g), achene yield (2976 and 2621 kg ha-1), biological yield (11363 and 8430 kg ha-1), oil contents (43.37% and 41.87%), and oleic acid (70.33% and 80.83%) over 2 yr of study. Hence it can be concluded that soil application of 62 kg ha-1 K followed by foliar application of 1% K + 0.1% B is the preferable fertilization strategy for sunflower for improved yield, seed oil contents, and oil quality.

Abstract Introduction. The main control measure for brown spot (BS) caused by Septoria glycines is through the application of foliar fungicide. However, the management of the disease could be accomplished through cultural and genetic practices. Objective. To analyze the evolution of BS in soybean under different production systems. Materials and methods. This study was conducted for two consecutive years (2020 and 2022), in Pergamino, Buenos Aires, using the soybean cultivar DM46i20. The management variables studied were cover crops (CC), rotations (Rt), and timing of foliar fungicide application (MAFF). The evaluated pathometric variable was the area under the progress curve of plant height with symptoms (ABCPAPS), and the quantitative physiology variable was grain yield (R) in kg/ha. Results. Agronomic management practices had a significant effect (p≤0.05) on R and ABCPAPS. CC and MAFF were independent variables and showed a significant response (p<0.0001) on R. On the other hand, there was a significant triple interaction (p<0.0001) among CC, Rt, and MAFF for ABCPAPS, and therefore, the data were explained based on this relationship. Conclusions. The implementation of cover crops, crop rotations, and foliar fungicide significantly reduced (p≤0.05) the evolution of BS in soybean cultivation. There was a significant negative correlation (p≤0.05) between soybean yield and the area under the progress curve of the plant height with BS symptoms.

Resumen Introducción. La principal medida de control de la mancha marrón (MM) causada por Septoria glycines, se realiza mediante la aplicación de fungicida foliar, sin embargo, el manejo de la enfermedad podría realizarse con prácticas de manejo cultural y genético. Objetivo. Analizar la evolución de la MM de la soja en diferentes sistemas de producción. Materiales y métodos. Este estudio se llevó a cabo durante dos años consecutivos (2020 y 2022), en la localidad de Pergamino, Buenos Aires, sobre un cultivar de soja DM46i20. Las variables de manejo fueron cultivos de cobertura (CC), rotaciones (Rt), momento de aplicación del fungicida foliar (MAFF). La variable patométrica evaluada fue el área bajo la curva de progreso de la altura de la planta con síntomas (ABCPAPS) y como variable cuantitativa fisiología sobre el cultivo el rendimiento (R) en granos en kg/ha. Resultados. Las prácticas de manejo agronómico tuvieron un efecto significativo (p≤0,05) sobre el R y el ABCPAPS. Las variables CC y MAFF fueron independientes y presentaron una repuesta significativa (p<0,0001) sobre el R. En cambio, hubo una triple interacción significativa (p<0,0001) entre los CC, las Rt y el MAFF para el ABCPAPS y, por lo tanto, los datos fueron explicados con base en esta relación. Conclusiones. La implementación de cultivos de cobertura, de rotaciones de cultivo y de fungicida foliar, redujeron significativamente (p≤0,05) la evolución de la MM en el cultivo de soja. Hubo una correlación negativa y significativa (p≤0,05) entre el rendimiento en soja y el área bajo la curva de progreso de la altura de la planta con síntomas de la MM.

Abstract Introduction. Corn is one of the oldest known food grains. With climate change and frequent and severe droughts, the water available in the soil will be considerably reduced. Water deficit affects maize crop development to varying degrees, and sensitivity to this stress varies at different development stages. Objective. To identify the phenological stages most sensitive to water deficit in maize. Materials and methods. The experiment was conducted during two growing seasons in 2020 and 2021 in El Ejido, Los Santos province, Panama, under semi-controlled conditions in the greenhouse facilities of the Instituto Coronel Segundo de Villarreal. The commercial corn hybrid ADV-9293 was used and agronomic management was carried out according to the recommendations of the Institute for Agricultural Innovation of Panamá (IDIAP). Plant height, leaf length and width, stem diameter, biomass and yield components, such as number of rows per ear, number of grains per row and 100-grain mass, were determined throughout the crop cycle. Soil moisture was also determined by the gravimetric method. Water deficit at different stages was generated by drought simulation. Results. The grain yields of the control were higher than the different treatments evaluated with 12.83 t ha-1, followed by the treatment with grain filling stress with 10.31 t ha-1. Two periods were determined to be more sensitive to water deficit; these were the stages from 20 to 35 and 40 to 55 days after planting. Water deficit in the different phenological stages of the crop had a negative impact on the relative chlorophyll content. Conclusion. The pre-flowering and flowering stages were more sensitive to water deficiency in maize.

Resumen Introducción. El maíz es uno de los granos alimenticios más antiguos conocido. Con el cambio climático y las sequías severas y frecuentes, se reducirá en gran medida el agua disponible en el suelo. El déficit hídrico afecta en diversos grados el desarrollo del cultivo de maíz y la sensibilidad a este estrés varía en las diferentes etapas de desarrollo. Objetivo. Identificar las etapas fenológicas más sensibles al déficit hídrico en el cultivo de maíz. Materiales y métodos. El experimento se realizó durante dos ciclos en los años 2020 y 2021 en El Ejido, Provincia de Los Santos, Panamá. Se desarrolló bajo condiciones semicontroladas en la casa de cultivo del Instituto Coronel Segundo de Villarreal. Se utilizó el híbrido de maíz comercial ADV-9293. El manejo agronómico se realizó según las recomendaciones del Instituto de Innovación Agropecuaria de Panamá (IDIAP). Durante todo el ciclo del cultivo, se determinaron las variables altura de planta, largo y ancho de hojas, diámetro del tallo, biomasa y los componentes del rendimiento como número de hileras por mazorca, número de granos por hilera y peso de cien granos. También, se determinó la humedad del suelo por el método gravimétrico. El déficit hídrico en distintas etapas se generó a través de la simulación de sequía. Resultados. El rendimiento de grano del testigo superó los diferentes tratamientos evaluados con 12,83 t ha-1, seguido por el tratamiento con estrés en el llenado de grano con 10,31 t ha-1. Se determinaron dos períodos más sensibles al déficit hídrico; los cuales son las etapas comprendidas desde los 20 a 35 y 40 a 55 dds. El déficit hídrico, durante las diferentes etapas fenológicas del cultivo, tuvo un impacto negativo en el contenido relativo de clorofilas. Conclusión. Las etapas de prefloración y floración resultaron más sensibles a la deficiencia hídrica en el cultivo del maíz.

Abstract Introduction. Quinoa downy mildew is a disease that causes economic losses and has been poorly studied.Therefore, researching quinoa’s response to the disease and treatment methods is a topic that requires further investigation. Objective. To describe how downy mildew infection affects quinoa plants and the non-traditional methods used to control this disease. Development. A systematic search was conducted to compile the results associated with P. variabilis in quinoa (Chenopodium quinoa Wild.) under various conditions. The analysis determined that factors such as incidence, severity, and disease tolerance depended largely on the quinoa grain variety and altitude (along with its climatic conditions). Plant height and yield per hectare were influenced by soil conditions, pest and disease treatment, and the planting day. Conclusions. The incidence and severity of downy mildew depended on the quinoa variety used. Other factors such as altitude or humidity also influenced disease progression, with infection rates close to 90 % in high humidity environments. Non-conventional methods for treating downy mildew included plant infusions such as chamomile and garlic, showing positive short-term results; however, they did not surpass conventional treatments with chemical fungicides.

Resumen Introducción. El mildiu de la quinua es una enfermedad que ocasiona pérdidas económicas y que ha sido poco estudiada, por lo que la investigación de la respuesta de la quinua a la enfermedad y las formas de tratamiento es un tema que debe investigarse con mayor profundidad. Objetivo. Describir cómo afecta la infección del mildiu velloso en la planta de la quinua y los métodos no tradicionales empleados en el control de esta enfermedad. Desarrollo. Se realizó una búsqueda sistemática a fin de realizar una recopilación de los resultados asociados al P. variabilis en la quinua (Chenopodium quinoa Wild.) en diversas condiciones. El análisis determinó que factores como la incidencia, la severidad y la tolerancia a la enfermedad del mildiu, dependieron en gran medida de la variedad de grano de quinua y la altitud (con sus condiciones climáticas). La altura de la planta y el rendimiento por hectárea estuvieron influenciados por las condiciones del suelo, el tratamiento empleado contra plagas y patógenos, y el día de siembra. Conclusiones. La incidencia y la severidad del mildiu velloso dependió de la variedad de la quinua con la que se trabajó. Otros factores como la altitud o la humedad también influyeron en el progreso de la enfermedad, con una infección cercana al 90 % en ambientes con alta humedad. Los métodos no convencionales para tratar el mildiu fueron infusiones de plantas como la manzanilla y el ajo, con resultados positivos a corto plazo; no obstante, no superaron a los tratamientos convencionales con fungicidas químicos.

Abstract Background: Maize landraces show remarkable diversity and environmental adaptability in Mexico. Nevertheless, few studies have explored physiological mechanisms used by different maize landraces to grow and yield in a particular agroecological region. Question: How do three landrace maize populations from contrasting maize races in southeastern Mexico, differ in their responses in terms of growth, chlorophyll fluorescence, and gas exchange? Studied species: Zea mays L. Study site and date: Yucatan, Mexico; 2017. Methods: The field experiment followed a complete randomized block design, with six replicates. Three contrasting maize landraces were evaluated as treatments. Response variables were vegetative traits, dry matter allocation, yield components, and maize physiological responses. Data were analyzed by one-way ANOVA and post hoc Tukey multiple comparison test (P ≤ 0.05). Results: Maize landraces showed differences in cycle length, plant morphology, and yield performance. The long cycle maize landrace Xnuc-naal, had tall plants that accumulated 17 and 21 % more dry matter than Xmejen-naal and Elotillo, respectively. The short-cycle maize landraces Elotillo and Xmejen-naal exhibit superior physiological responses leading to higher grain yields compared to the Xnuc-naal. Conclusions: The landrace Xnuc-naal stood out for its ability in forage production, whereas Elotillo and Xmejen-naal exhibited notable physiological efficiency in grain production in southeastern Mexico.

Resumen Antecedentes: Las razas nativas de maíz muestran una notable diversidad y adaptabilidad en México. Sin embargo, pocos estudios han explorado los mecanismos fisiológicos utilizados por las diferentes razas de maíz para crecer y producir en una región agroecológica en particular. Pregunta: ¿Cómo difieren en sus respuestas en cuanto a crecimiento, fluorescencia de la clorofila e intercambio de gases tres variedades de maíz que provienen de razas contrastantes del sureste de México? Especie estudiada: Zea mays L. Sitio y fecha del estudio: Yucatán, México; 2017. Métodos: El experimento de campo siguió un diseño de bloques completamente aleatorios, con seis repeticiones. Se evaluaron tres variedades nativas de maíz contrastantes como tratamientos. Las variables de respuesta fueron rasgos vegetativos, distribución de materia seca, componentes del rendimiento y respuestas fisiológicas de las variedades de maíz. Los datos fueron analizados mediante ANOVA de una vía y la prueba de comparación múltiple de Tukey (P ≤ 0.05). Resultados: Las variedades locales de maíz mostraron diferencias en la duración del ciclo, morfología de la planta y rendimiento. La variedad tardía Xnuc-naal, tuvo plantas altas que acumularon un 17 y 21 % más materia seca que Xmejen-naal y Elotillo, respectivamente. Las variedades precoces Elotillo y Xmejen-naal exhibieron una respuesta fisiológica superior que llevó a un rendimiento de grano superior al de Xnuc-naal. Conclusiones: La variedad de maíz Xnuc-naal destacó por su capacidad para la producción de forraje, mientras que Elotillo y Xmejen-naal demostraron una eficiencia fisiológica notable en la producción de grano en el sureste de México.

ABSTRACT The interaction between bean (Phaseolus vulgaris L.) genotypes and N-fixing microorganisms has the potential to be utilized in sustainable agricultural production. Thus, the aim of this study was to verify the effects of the interaction for growth, production and nodulation characteristics between the bacteria Rhizobium tropici and Azospirillum brasilense among different bean genotypes. The experiments were conducted in the Selvíria, Mato Grosso do Sul, Brazil, in 2018 and 2019, in randomized block design with three replicates in a 20 × 3 factorial scheme; 20 common bean genotypes were tested under three forms of inoculation (no inoculation, inoculation with R. tropici, co-inoculation of R. tropici + A. brasilense). The number of grains per pod and nodule mass had the most significant direct positive effect on grain yield. For nodulation, a positive correlation of strong magnitude was observed between mass of the aerial part and number of pods per plant (0.68), stem diameter and mass of nodules (0.92) and first pod insertion height and number of nodules (0.64). In the path analysis, the number of grains per pod had the most significant direct effect (0.57) on the grain productivity variable. Regarding nodulation characteristics, selection for nodule mass was preferred due to its direct effect on grain yield as opposed to the number of nodules, which has a negative effect. This suggests an advantage of larger nodules with greater individual mass than a large number of small nodules for both improved yield and N fixing by common bean plants.

ABSTRACT Maize (Zea mays L.) is highly sensitive to salt stress, which poses a threat to its production, especially with predicted increases in salinity due to climate change. Enhancing salt tolerance in maize is critical to mitigating these adverse effects, sustaining its production, and ensuring global food security. This study aimed to evaluate the effects of exogenously applied lipoic acid or Si, alone or in integration with soil application of vermicompost-tea on physio-biochemical components, antioxidant defense systems, growth, and yield of maize plants exposed to salt stress. The application of vermicompost-tea was carried out as a soil treatment incorporated into irrigation water at a concentration of 200 L ha-1, and administered in three equal doses in irrigation water within the last 10 min of drip irrigation. Silicon was applied at a rate of 6 mM using potassium silicate and lipoic acid was applied at 0.1 mM. Silicon and lipoic acid were applied three times at 25, 40, and 55 d after planting. The results indicated that the integrative application of soil-based vermicompost-tea with exogenously applied Si or lipoic acid significantly enhanced all studied parameters. Specifically, the combination of Si with vermicompost-tea exhibited the highest improvement percentage compared to untreated control in chlorophyll a (60.3%), chlorophyll b (72.7%), carotenoids (69.9%), net photosynthetic rate (111%), transpiration rate (134%), stomatal conductance (129.5%), relative water content (28.4%), membrane stability index (44.3%), N (33.4%), P (71.9%), K (39.7%), Ca (89.9%), K/Na (81.2%), total soluble sugars (63.7%), proline (60.1%), ascorbate (44.4%), glutathione (83.5%), and α-tocopherol (72.1%). These positive effects were reflected in enhancing yield traits under salt-affected soil conditions by enhancing plant height (25.1%), number of grains per row (43.3%), number of rows per ear (26.7%), 1000‐grain weight (25.9%), grain yield (45.4%), and biological yield (42.8%) compared to untreated control.

ABSTRACT Heat and drought stress, which often co-occur due to water evaporation, are two major abiotic factors limiting the production of rice (Oryza sativa L.) It is crucial to enhance understanding of the effects of these abiotic stresses in rice, particularly for rice-producing countries like Malaysia, which has yet to achieve rice self-sufficiency. This greenhouse study was conducted to evaluate the morphological changes of two important Malaysian cultivars (‘MR219’ and ‘MR303’) at vegetative, reproductive, and ripening stages, as well as their physiological response and yield components under normal (control), heat, drought, and combined heat-drought stress conditions. Individual heat stress greatly influenced rice growth and yield, with significant differences (p < 0.01) observed across all examined parameters except the grain to leaf area index ratio (GtoLAI). Conversely, individual drought stress mostly affected yield-related parameters, with significant differences (p < 0.01) in grain weight (GW), harvest index (HI), and percentage of filled grain (%FG). Interestingly, the combined stresses in this study did not significantly affect plant height (PH) for all growth stages and most yield-related traits (HI, GW, and GtoLAI). The majority of the significant changes (p < 0.01) were observed on physiological traits, including chlorophyll a (Chl A) and b (Chl B). We found a positive correlation between HI and %FG (R2 = 0.3974**) under heat and drought stress, indicating that improving either of these traits can boost rice production. Collectively, our study revealed that the individual effects of heat and drought on rice growth and yield can differ from the effects of combined stress.