Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Background. Guinea fowl production is gaining much attention and recognition across the globe.  However, the bird’s inability to lay fertile eggs all year round is one of the key challenges to commercialization and intensive production. Objectives/hypothesis. This study examines the photoperiod effect on growth, reproductive traits, hormonal and thermo-physiological response of the Pearl Guinea fowls. This study hypothesize that photoperiod will solve the seasonal breeding behaviour among Guinea fowls. Methodology. This study was conducted at Dawu in the Ashanti Region of Ghana. Birds used for this investigation were subjected to different photoperiod: 12HL:12HD, 14HL:10HD, 16HL: 8HD and 18HL:6HD using a white bright LED Energy saving bulbs of 120 watts with light intensity of 5.60 lux and kept from day-old to 168 days in a completely randomized design. Results. Birds subjected to 18HL:6HD treatment group recorded the highest (P < 0.05) final body weight (1757.23 g/bird), body weight gain (1734.33 g/bird), daily weight gain (10.32 g/bird), total feed intake (6627.3g/bird) and daily feed intake (39.45 g/bird). Birds subjected to 14HL:10HD had the best (3.809) feed conversion ratio. Birds subjected to 18HL:6HD laid earlier (P < 0.05) (130 days) with the lowest (P < 0.05) egg weight of 23.33 g. While birds subjected to 12HL:12HD reached 184 days before starting egg production (P < 0.05) but recorded the highest (P < 0.05) egg weight of 37.33 g. Birds in the 18HL:6HD treatment group recorded the highest (P < 0.05) percentage fertility (86.94) followed by 16HL:8HD (79.86 %) and 14HL:10HD (79.44 %). Hatchability was very high among birds subjected to 16HL:8HD and 18HL:6HD with mean values of 82.89 % and 82.69 % respectively. FSH, LH, Prolactin and testosterone levels in the blood increased with increasing photoperiod (P < 0.05). Birds on the 18HL:6HD treatment had the highest (P < 0.05) body temperature (41.57 oC), pulse rate (270.87 Beats/min), respiratory rate (42.69 Breath/min) and rectal temperature (42.95 oC). Implications. Except for birds subjected to 12HL:12HD, birds across the other photoperiod groups were able to lay fertile eggs across the period of study. Conclusion. This study concludes that, photoperiod levels up to 18HL: 6HD promote rapid growth, reduce age at first egg laying, improve fertility and hatchability of Guinea fowl eggs and boost hormonal production.

Antecedentes. El maíz (Zea mays L.) es una planta alógama en constante mejoramiento mediante diversos métodos de selección, comenzando con la selección masal hacia la mejora genética de poblaciones. Objetivo: Evaluar el avance genético en la variedad de maíz Marginal 28T, utilizando el método de selección recurrente de medios hermanos mazorca por surco en el trópico. Metodología: Se comparó dos periodos de selección (1996-2000 y 2018-2022) del núcleo genético de la variedad Marginal 28T. Con las semillas remanentes del período 2018-2022, se establecieron parcelas de evaluación rendimiento en un diseño de bloques completos al azar, y se compararon con los resultados reportados en el periodo 1996-2000; para conocer si existió cambios varietales desde 1984 año de liberación de la variedad, se utilizó las semillas del año 2022, en cinco localidades. Resultados: Entre los periodos de selección de núcleo de semilla genética 1996-2000 y 2018-2022 del maíz Marginal 28T, el rendimiento de semilla mejoró 0.75 t·ha⁻¹, con una ganancia genética de 0.042 t·ha⁻¹·año⁻¹. La evaluación del rendimiento agronómico de la semilla genética reveló una reducción de 6 días en la floración, con un aumento en el rendimiento de grano de 0.86 t·ha⁻¹. La caracterización varietal mostró uniformidad en características clave como textura de grano y cambios notables en el color del grano de amarillo rojizo a amarillo naranja, y una mejora en el rendimiento de grano comercial, de 3.50 t·ha⁻¹ en 1984 a 5.57 t·ha⁻¹ en 2022. Implicaciones: Se resalta la importancia del uso continuo del método de selección recurrente de familias de medios hermanos mazorca por surco para maximizar el rendimiento y la estabilidad varietal del cultivo del maíz amarillo duro en trópico. Conclusión: La variedad de maíz amarillo duro Marginal 28T ha demostrado un avance genético en relación con su rendimiento y color de grano desde su liberación como variedad de polinización libre en 1996.

Background: The production of high quality seedlings locally is an area of opportunity for the development of organic agriculture in south-southeastern Mexico. In the case of jalapeño bell pepper production, a vegetable with high demand for national and international consumption, the use of alternative substrates to produce organic seedlings is a necessity in tropical and subtropical regions. Biochar combined with organic amendments has been shown to be potentially beneficial in a variety of crops in support of organic agriculture. Objective: To evaluate the effect of biochar used in combination with bocashi to produce jalapeño bell pepper seedlings. Methodology: Seven treatments were defined, biochar at 10, 20, 30, 30, 40 and 50 % + bocashi, plus two controls, a commercial organic fertilizer (peat most at 70 % + perlite at 30 %) and another natural soil of the region (alluvial soil). The research was descriptive and under a completely randomized design the systems were exposed with four replicates, each experimental unit was represented by 33 cavities in germination trays of 77 spaces, in each germination tray two replicates were established. The biochar was activated with efficient microorganisms through an anaerobic fermentation process. Hybrid jalapeño bell pepper seed was used. A total of 132 seeds were sown for each treatment in 924 planting points in total. Management consisted of daily irrigation. In addition, a foliar biofertilizer based on a mixture of efficient microorganisms and earthworm leachate was applied weekly. The variables evaluated were days to emergence, number of leaves, plant height, stem diameter, total length, green and dry weight of seedlings. ANOVA and Tukey's mean tests were performed. Results: The use of biochar mixed with bocashi in its different proportions benefited seedling emergence and gave better results in the variables evaluated than the controls. The proportions with the highest percentage of bocashi excelled in all variables. Implications: The combined use of biochar with bocashi represents a substrate with potential to produce organic seedlings of jalapeño peppers in the subtropical regions of south-southeastern Mexico. Conclusions: The combined use of bocashi (80%) and biochar (20%) constitute a technically feasible alternative for its implementation in the production of jalapeño bell pepper seedlings. This research contributes to the development of organic agriculture in the south-southeast of Mexico.

Background: The growing demand for foods such as corn or soy has favored the study and implementation of biotechnologies that use agroindustrial waste and transform them so that they can be used to obtain alternative diets for animals with a high biological value. Objective: To increase the feed value of sugarcane bagasse through fermentation with probiotic microorganisms under solid-state conditions. Methodology: A diet based on by-products of sugarcane bagasse harvest treated by solid-state fermentation (SSF) was prepared. The fibrous material was collected, dried, ground, and mixed in a proportion of 1.0 and 2.0 inclusion with alfalfa flour (1.5), molasses (0.25), sodium sulfate (0.05), calcium carbonate (0.05), mineralized salt (0.05), urea (0.15), microbial preparation (0.25), and potato (6.7 or 5.7, respectively). The prepared feed was subjected to FES and evaluated by compositional and microbiological analysis. The effect of the percentage of sugarcane bagasse inclusion on obtaining dry matter, humidity, ash, ethereal extracts, crude protein, neutral and acid detergent fiber, organic matter and in situ digestibility of dry matter was analyzed. Results: The inclusion percentage significantly affects the production of ash (7.23 and 6.63%, respectively), crude protein (16.3 and 14.1%, respectively), organic matter (92.7 and 93.3%, respectively), and in situ digestibility (74.6 and 63.8, respectively). The microbiological analysis determined that the count of lactic acid bacteria and aerobic mesophiles increased with fermentation time; no growth of molds, yeasts, or Salmonella was observed. Implications: Solid-state fermentation proves its value as a sustainable strategy, a cost-effective alternative, and an easily applicable approach for the utilization and valorization of agroindustrial waste by incorporating it into functional diets for sheep. Conclusion: Under the conditions of this study, it was demonstrated that the biological value of sugarcane bagasse can be effectively increased through solid- state fermentation when combined with other raw materials, making it a viable component in formulating diets for sheep.     

Background. The information and communication technologies are considered important for the rapid and efficient communication and dissemination of information among farmers, which can facilitate the diffusion of technologies. Objective. To identify the most relevant technologies to dairy farmers and to analyse farmers’ perception of the information contained in the infographics shared via WhatsApp™. Methodology. To collect the data, a questionnaire was applied to 108 dairy farmers from central Mexico. Farmers were grouped using multivariate statistics such as factor and cluster analysis. The four most important technologies to farmers were identified and infographics of maize silage, artificial insemination (AI), concentrate feeding, and heat-service were designed and distributed via WhatsApp™™. A Chi-Square test was conducted to analysed the dichotomous responses about farmers’ perception of receiving and sending infographics via WhatsApp™. The infographics were also evaluated using a five-point Likert type scale and Kruskal-Wallis test was used to analyse the data. Results. Four factors that explain 73.3% of the cumulative variance were identified. Four groups were identified. Group 1 had the largest farm size, group 2 had the most available family labour, group 3 had the youngest farmers with better schooling, and group 4 had the highest level of technical assistance. Farmers in groups 1 and 2 found the infographics on maize silage and AI to be informative and well-understood. Farmers in group 3 found the concentrate feeding infographic to be informative, but 73% reported that pH and ruminal acidity were terms difficult to understand. Meanwhile, 87% of farmers in group 4 found the heat-service infographic to be unimportant, but easy to comprehend. Implications. The research contributed to identifying the usefulness of infographics in communicating information on technologies important to farmers. It also identified areas of interest achieved through their use in extension services.  Conclusions. It is concluded that the infographics and WhatsApp™ are very useful tools for sharing information and communication of technologies. Therefore, the combination of these tools could improve extension services for dairy farmers in rural areas. 

Background: Guava scab is a disease caused by Pestalotiopsis clavispora, and chemical agents are used for its control. An alternative is the use of antagonistic fungi such as Trichoderma spp., which has been extensively studied and has a low environmental impact. Objective: In this study, the biological effectiveness of Trichoderma strains against Pestalotiopsis sp. was evaluated. Methodology: Dual bioassays were established, where mycelial discs of Trichoderma and Pestalotiopsis were placed equidistantly on PDA medium to evaluate the antagonist's behavior against the pathogen. In the field, six Trichoderma strains, two fungicides, one insecticide, and the wateronly control were evaluated. At harvest, the incidence and severity of the disease, as well as the biological effectiveness of the treatments, were determined. Results: The bioassays showed that most Trichoderma strains are good competitors for colonizing the medium. They also showed mycoparasitism and reduced Pestalotiopsis growth. Implication: In the field, two Trichoderma strains achieved a reduction in the percentage of damaged fruit, lower severity, and greater effectiveness, similar to one of the fungicides and the insecticide. Conclusion: These strains can be considered in field level management for guava stem blight control, with a lower environmental impact.

Background: The root-knot nematode Meloidogyne paranaensis is one of the main phytosanitary problems in coffee crops, as it causes premature death of plants. In localities in central Veracruz, Coffea canephora plants tolerant to this nematode have been detected, which can be used as rootstocks in infested areas. Objective: To select plants that show tolerance in the field and to isolate and identify fungi associated with the rhizosphere of these coffee plants. Methodology: Plants infested with nematodes were selected and root samples were taken to quantify population density and corroborate the species. Fungi were isolated and identified from the rhizosphere soil. Five fungi were selected to observe the in vitro infection process on M. paranaensis eggs. Results: 18 plants that showed tolerance to M. paranaensis were selected. Twenty strains of fungi belonging to 7 genera and 16 species were obtained. The genera Penicillium and Fusarium were the most frequent. Clonostachys rogersoniana was the only fungus that showed parasitism against M. paranaensis eggs in vitro. Implications: The 18 selected plants show tolerance in the field, and it is necessary to conduct tests with controlled inoculations of M. paranaensis with clones and progeny. Tests on the nematophagous capacity of C. rogersoniana should continue. Conclusion: In the study area there are plants with tolerance to M. paranaensis and they can be used as rootstocks. The fungus C. rogersoniana is capable of infesting M. paranaensis eggs and is a potential biological control agent for this nematode.

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