La caracterización fisicoquímica constituye un insumo estratégico para programas de selección y mejoramiento del tomate, orientados a la conservación y el aprovechamiento de los recursos fitogenéticos locales, así como a la diversificación de productos hortícolas adaptados a las condiciones agroclimáticas del país. Se presentan los resultados de la caracterización de frutos de 18 accesiones de tomate (Solanum spp.) silvestres y cultivadas recolectadas en diferentes regiones agroecológicas de Venezuela, y cultivadas en invernadero para su caracterización en el marco del Proyecto de Desarrollo de Germoplasma de Tomate, ejecutado por el Centro Nacional de Investigaciones Agropecuarias (CENIAP) del Instituto Nacional de Investigaciones Agrícolas (INIA). Se emplearon protocolos estandarizados para la medición de variables físicas (peso, tamaño, forma, número de lóculos, firmeza y rendimiento en jugo), y químicas (contenido de sólidos solubles totales, acidez titulable, pH y contenido de carotenoides totales). El análisis de varianza y las comparaciones de medias indicaron diferencias altamente significativas entre las accesiones para la mayoría de las variables estudiadas, evidenciando una amplia variabilidad genética entre los materiales evaluados. El análisis de componentes principales (ACP) redujo la dimensionalidad de los datos, explicando un 46,6 % de la varianza total en el primer componente (CP1) y un 15,1 % en el segundo (CP2). Asimismo, el análisis de conglomerados reveló la formación de cuatro grupos diferenciados, cuyas medias presentaron diferencias significativas en diversas variables fisicoquímicas. Estos resultados permitieron identificar accesiones con características deseables para consumo fresco, procesamiento o mejora genética.

Cocoa seeds are recalcitrant, resulting in a faster loss of viability with storage time and the tetrazolium test is an alternative to determine the viability of these seeds as quickly as possible. The objective of this study was to develop a tetrazolium test protocol for cocoa seeds to assess seed viability. Seeds were extracted from fruits and after the processing were subjected to the tetrazolium test considering 7 times in tetrazolium solution (2, 3, 4, 5, 6, 7 and 8 hours) and 2 concentrations of tetrazolium solution (0.05 % and 0.075 %). Before this, seeds were soaking for 6 hours in germination paper and the seed coats were removed. During the immersion on tetrazolium solution, seed were maintained in a germination chamber at 42 °C. After this, seeds were categorized into 4 classes, according to the coloration of embryonic axis, with the living tissues being dyed with light pink color while dead tissues were non-colored. To confirm the results of tetrazolium test, a germination test was carried out to associate the percentage of germination with the percentage of viable seeds obtained by the tetrazolium test. Considering this, the recommended immersion time in the tetrazolium solution is 3 hours with a concentration of 0.05 %.

During postharvest storage oca tubers can pass for different stages, in which bioactive compounds can change their content; and specifically the sprouting stage, can alter significatively these components. Therefore, this study evaluated the sprout length, loss weight, reducing sugar content, total phenolics content, and antioxidant capacity of three oca tuber varieties (yellow, purple, and orange) during postharvest storage. Oca tuber varieties were stored at 19 °C ±1 ºC and relative humidity of 85% ±1%. A factorial design was used to evaluate the effect of oca variety and postharvest storage time (0, 15, 30, 45, 60, 75, and 90 days). The sprout length of the three oca varieties begin to growth at 15-30 days of postharvest storage, which indicated that dormancy period was broken, moreover, the sprout length was increased until 90 days of storage. Yellow oca had the longest sprout length (26.4 cm) and the highest loss weight (22.55 %) at 90 days of storage, which indicated an effect of oca variety and postharvest storage time (p value≤0.05). The reducing sugar content, total phenolics content, and antioxidant capacity of the three oca varieties exhibited variable behaviors during storage time and initially oca tubers showed a reduction in their values, which were presumably related to the stabilization period. The postharvest storage time and oca variety produced different physiological changes in the oca tubers, which affect the sprout length, weight loss, reducing sugars, total phenolics content, and antioxidant capacity.

Due to their high dry matter production and balanced nutritive value per unit area, Elephant grass cultivars are excellent for bulky supplementation during the dry season. The objective was to evaluate the productivity and nutritive value of the BRS Capiaçu cultivar through different cutting ages after planting. The experimental design was conducted in completely randomized blocks, with four cutting ages: 60, 90, 120, and 150 days, each with five replications (blocks), totaling 20 experimental units, covering a total area of 12 m². As age advanced, linear increases in productivity were observed (p≤0.01), reaching an average height of 4.60 m, a green matter productivity of 252.60 t·ha-1, and a dry matter productivity of 67.36 t·ha-1 at 150 days after planting. Regarding nutritional value, linear increments (p≤0.01) were found in dry matter, organic matter, and neutral detergent fiber levels, while mineral matter and crude protein exhibited a linear reduction (p≤0.01). However, no effects (p>0.17) were observed with advancing cutting age after planting for acid detergent fiber, and hemicellulose variables. It is concluded that increasing the cutting age reduces the forage's nutritional value. From this perspective, the 90-day age proved to be more suitable for cutting BRS Capiaçu elephant grass.

La totora en el ámbito peruano del lago Titicaca, aún se aprovecha como alimento para consumo humano, siendo necesario conocer sus cualidades nutricionales y potencialidades, por ello se plantea caracterizar su composición nutricional y el valor etnobotánico. Se realizaron análisis proximales de tallos basales, rizomas y brotes rizomáticos (“chullu”, “siphi” y “saka” respectivamente, por sus nombres locales de las partes consumibles), en seis réplicas cada una y tres para análisis de minerales (Fe, P, K, Ca y I) bajo espectrofotometría UV/VIS y análisis volumétricos; además se entrevistó a 45 personas de comunidades aledañas al Titicaca, para conocer aspectos básicos de su importancia etnobotánica. El chullu y saka presentaron similares niveles de humedad (93,17 % y 92,87 %) y significativamente menor en el siphi (75,89 %); todos presentaron altos contenidos de cenizas (6,04 a 9,85 %), el chullu y saka fueron ricos en fibra (22,59 % y 20,87 %) y el siphi alto en carbohidratos (65,91 %), los tres presentaron moderados niveles de proteínas (6,97 a 10,44 %). El siphi prevaleció en contenidos de calcio y hierro (12,38 y 1,57 mg.(100g)-1, respectivamente); destacando altas concentraciones de yodo en los tres órganos, alcanzando 271,33 mg.(100g)-1 en siphi, superior a cualquier alimento convencional. Prácticamente el 100 % de pobladores manifestaron conocer la totora como alimento para humanos, con el mayor reporte de uso para el chullu (65,08 %) y el menor para el siphi (12,70 %). Por sus cualidades nutricionales y valor etnobotánico, S. californicus representa una importante alternativa como recurso alimenticio no convencional.

Corn crop (Zea mays L.) is one of the pillars of Brazilian agriculture, with a wide cultivation area and high productivity; Brazil is the world's second largest exporter of this cereal. For this reason, the aim of the present study was to evaluate the viability of biopriming of corn seeds with a product based on Bacillus subtilis, at different concentrations, up to 120 days of storage. The research was carried out in the seed technology laboratory of the State University of Londrina (UEL), using the commercial corn seeds Balu 366. The experimental design was completely randomized, with four replications, in a 7 × 5 factorial scheme, with seven concentrations of the commercial product based on Bacillus subtilis (Serenade) for seed biopriming (0.0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0 %) and five storage periods in a cold chamber (0, 30, 60, 90, and 120 days). The evaluation of the physiological quality of the seeds occurred through germination, cold and seedling length tests. The variables analyzed were first germination count, germination percentage, vigor from the cold test, shoot length, length of the longest root, shoot dry mass, and root dry mass. For the statistical analysis, adjustments of regression models with the best fit were made. The biopriming of seeds proved to be an advantageous practice to enhance the physiological quality of the seeds under storage; it should be carried out at a concentration of 2.5 %, due to its economic viability, considering its efficiency equivalent to the highest concentrations. The biopriming of seeds proved to be a viable practice for seed storage for up to 60 days.

Eugenia stipitata is a fruit species from the Amazon that is important in traditional medicine due to its therapeutic properties. Estimates of seed viability in this species are still scarce, and it is necessary to develop rapid tests to determine the quality of the seeds. The aim of this study was to determine the applicability of the tetrazolium test to estimate viability and germination in seeds of E. stipitata with and without storage. The design was completely randomised in a 2 x 2 factorial scheme with 10 replications. The results of the tetrazolium and germination tests show that seeds of E. stipitata lose their viability when stored for six months in water at ambient temperature. Neither small nor large seeds stored for six months in water at ambient temperature are recommended for use with the tetrazolium test. Small, freshly harvested, unstored seeds show a germination potential of 100%. The tetrazolium test is efficient in determining the viability of small and large seeds of Eugenia stipitate with no storage.

La generación de información que sirva de argumento en la búsqueda de alternativas de manejo sostenible de la irrigación en arroz es una demanda actual inevitable. Ante ello, este estudio tuvo como objetivo la evaluación del riego tradicional (inundación continua) a través de la producción del cultivo, la eficiencia de uso de agua y la emisión de metano; tomando como referencia una alternativa de riego sin inundación (aeróbico), en el cual se mantuvo la humedad del suelo entre saturación y alrededor de capacidad de campo. Con estas dos alternativas de riego se instaló un experimento de cuatro parcelas cuadradas de 25,0 m de lado, definiéndose nueve puntos de muestreo de 4,0 m2 dentro de cada una de ellas. Se utilizó la variedad de arroz INIAP 11 de uso local, con siembra por trasplante. El manejo del riego se llevó a cabo bajo el método de la tina de evaporación, junto con el registro de tensiómetros para el control de la humedad. En el cultivo se evaluó el macollamiento, los granos vanos (%), el peso de 1000 granos (g) y el rendimiento (kg·ha-1). En la medición del metano se utilizaron dos cámaras acrílicas de 1,0 m x 1,0 m x 1,2 m, junto con un medidor portátil del gas y de la temperatura. No se detectaron diferencias significativas en la producción del cultivo, se evidenció un incremento sustancial de la eficiencia de uso de agua de 3,649 m3·kg-1 a 0,312 m3·kg-1. La tasa de emisión de metano fue significativamente (P≤0,05) superior en el riego tradicional, con una media de 2,92 mg·m-2·h-1; mientras que, en la irrigación aeróbica, este valor fue de 1,07 mg·m-2·h-1. Se concluyó que la alternativa de riego propuesta presenta ventajas en todos los parámetros evaluados respecto del riego tradicional.

The production system influences the cadmium (Cd) content and mycorrhization in cocoa plantations. The objective of this study was to determine the effects of different production systems on Cd uptake and the presence of mycorrhizas in cacao clones in field conditions, in the Peruvian Amazon. Twelve subplots of 108 m2 were selected in representative cocoa cultivation systems under agroforestry (AF) and monoculture (MON), with the cocoa clones ICS and CCN. Significant differences and data distribution were evaluated using ANOVA, principal component analysis, and Tukey's tests. Mycorrhizal colonization was higher in the AF_ICS system (71.11%) while the length of the extraradical mycelium was higher in the AF_CCN system (17.23%). The highest Cd content in soils was found under the AF_CCN and AF_ICS systems, both with 0.39 mg kg-1. The Cd content in cacao roots, leaves, and beans were higher in the MON_CCN system with 1.87, 2.06, and 1.12 mg kg-1 respectively. Cocoa monocultures (with both clones) generally showed lower levels of mycorrhizal colonization than agroforestry systems, which in turn (also for both clones) presented higher Cd content in beans, even exceeding the limit established by the world health authorities.

Genetic improvement programs in cacao (Theobroma cacao L) have focused on obtaining new varieties with high yield and resistance to diseases. However, drought tolerance response has not been considered enough in order to face the climate change emergency. Events such as prolonged droughts or excessive rainfall can affect the pollen production of cacao flowers and others reproductive characteristics. Hence, this study was proposed to learn about the hydric deficit influence on pollen production of four Ecuadorian cacao genotypes. The results indicated statistical differences between CCN-51 and the "National" clones (P≤0.05). CCN-51 reached the highest pollen production values in the wettest treatment (26,546 ±100) compared to the “National” clones, which had no differences among them. There was a positive correlation between pollen production and the highest irrigation treatments (r=0.78), observing that while the water level was the highest, the pollen grain formation (PGF) increased, and the opposite when the water level diminished. It is concluded that the adequate water amount in the soil can increase pollen production. However, it is essential to emphasize the strong genetic influence on drought tolerance traits that could be severely affected by climatic changes. The CCN-51 and EET-575 clones should be considered when planning to develop drought-tolerant hybrids of cacao.