Revista de la Facultad de Agronomía de la Universidad del Zulia

Morpho-agronomic characterization of native maize populations (Zea mays L.), province of Manabí, Ecuador

Wilson Murillo — 2024-09-16

Ecuador is a country with a wide genetic diversity of maize and there are populations of native maize conserved by farmers that have not yet been characterized. These genetic resources could be conserved and used in plant breeding programs. The objective of this research was to characterize the morpho-agronomic diversity of 38 populations of native maize from the province of Manabí, Ecuador, using 19 quantitative and 11 qualitative morpho-agronomic descriptors. During the dry season of 2022 (July - December) at the Portoviejo Experimental Station of the National Institute of Agricultural Research (INIAP), plots of 8 m² were established for each population of native maize, with 0.3 m between plants and 0.8 m between furrows and each furrow was 5 m long. Cluster analysis showed the formation of four groups, where the populations of hard kernels with large ears and soft kernels with short ears were separated into different groups. The quantitative variables ear height, panicle length, percentage of lodging, number of kernels per row and biomass of the inflorescence rachis recorded "D" indices of 0.75, showing themselves as discriminant variables in the formation of the groups, while the most discriminating qualitative variables were kernel type (χ2 = 49.09***, P= 0.742, V= 0.64), kernel color (χ2= 51.955***, P= 0.75, V=0.64), row arrangement (χ2= 18.11*, P=0.56, V=0.39), and kernel surface shape (χ2 = 20.52*, P=0.58, V=0.41). The native maize races identified were Candela, Cubano, Tuxpeño, Tusilla, and Uchima, observing significant genetic diversity in the populations studied. It was concluded that the characterized native maize populations were a valuable genetic resource for the conservation and use of this cereal.

Comparison of weed control methods in rice in the rainy and dry seasons

Byron García — 2024-09-16

Integrated weed management strategies are crucial to reduce crop production costs. The objective was to compare weed control techniques according to their efficiency and profitability in rice cultivation during the rainy and dry seasons. It was carried out under the quasi-experimental modality with the Student's t-test under a descriptive research type. Structured questionnaires were administered to 70 rice farmers in the area. Weeds were identified in areas every 10 m² within the rice crop, 10 and 15 days after sowing. The efficiency (E) of weed management in rice crops was calculated by applying the formula . The results showed that manual weeding has a monthly frequency, being used both in the rainy season (40 %) and in the dry season (44 %). The frequency of herbicide application was adjusted to the crop stage in the rainy season (39 %) and in the dry season (46 %). The efficiency (E) using the mechanical method was below one month during the rainy and dry seasons, registering 43%. Manual weeding showed an E of 49 % in the rainy season and 42 % in the dry season for up to 30 days. The combination of herbicides: Metsulfuron-methyl + Quinclorac; pyrazosulfuron-ethyl + Quinclorac, exhibited an E greater than 80 %, for more than 30 days in both seasons. The highest profitability was in the rainy season, thus presenting mechanized control USD 0.09 in rainfall and USD 0.04 in drought, chemical control USD 0.09 in rainfall and USD 0.07 in drought, and manual weeding USD 0.10 in rainfall and USD 0.06 in drought, for every dollar spent during the cultivation of rice.

Morphological response of native maize (Zea mays L.) seedlings to contrasting nitrogen environments

Jenaro Reyes-Matamoros — 2024-09-17

Nitrogen plays a vital role in plant metabolism, influencing growth and development, particularly in crops like maize (Zea mays L.). This study aimed to evaluate the morphological response of maize seedlings to different nitrogen levels. The design was a completely randomized factorial arrangement of 4 x 2, involving four maize cultivars and two nitrogen levels.The variety Sb 302 Berentsen and three native varieties originating from Tecamachalco, Puebla, Mexico were studied. For a period of 14, 21, 28 and 35 days, seedlings were grown in nutrient solution with 10 % and 100 % nitrogen levels under hydroponic conditions. The results revealed significant variability in seedling morphology, particularly in root architecture and dry weight, between the 10 % and 100 % nitrogen treatments. High coefficients of variation were observed in the lengths of crown and seminal roots, alongside significant correlations between root and seedling dry weights at both nitrogen levels. Additionally, a strong correlation was found between root length and number under the 10 % nitrogen treatment. The results highlight the critical role of nitrogen in maize seedling development and the interaction between nitrogen concentration and maize variety, particularly in primary root length. The study improves understanding of nitrogen's role in optimizing maize growth and suggests strategies to enhance nitrogen use efficiency across different maize varieties.

Name of the xerophytic communities of the Ciénaga de La Palmita, Zulia state, Venezuela

Antonio Vera — 2024-09-26

The designation of deciduous thorny xerophytic shrublands is proposed for the plant communities xerophytic of the Ciénaga de La Palmita, Zulia state, Venezuela. The research was carried out in two areas: the southern sector of the xerophytic forest and the xerophytic enclave of the isleta El Hicacal of the Wildlife Fauna Reservoir Ciénaga de La Palmita and Isla de Pájaros.Tours, field explorations and collection of botanical samples were carried out (september 2019-february 2020) during the dry and rainy periods, and emphasis was placed on floristics, life habits and average height of individuals. The predominant biotype was the arboreal one and presented an average height of 6.5 and 7.9 m (low height) for each area respectively, thus designating the term shrublands. The xerophytic and thorny traits were present in the families with the highest number of species (Cactaceae, Euphorbiaceae, Fabaceae and Poaceae), highlighting leafless species, with aquiferous parenchyma, photosynthetic stem, thick leaf cuticles, compound leaves, thorns, spines and underground organs, giving them the qualifiers xerophilous and thorny. The term deciduous resulted from the high variety of deciduous species compared to the reports made for other communities in arid and semiarid areas of the country. The denomination of deciduous thorny xerophytic shrublands constitutes a new denomination for the studied area, appropriate to be included in the Planning and Use Regulation Plan (PORU) of said biotic space and provides precise guidance on the administration and management of the natural plant resources of this Area Under Special Administration Regime (ABRAE).

Productive and economic potential of the application of biofertilizer in hybrid corn DAS 3383

José Vera — 2024-09-27

The excessive and inappropriate use of synthetic fertilizers has the potential to cause significant environmental and economic issues. The utilization of biofertilizers represents a sustainable and environmentally friendly alternative for the enhancement of crop productivity. Accordingly, the present study evaluated the productive and economic behavior of applying biofertilizers on hybrid corn DAS 3383 under a completely random block design, with five treatments and three repetitions. The following treatments were employed: a control treatment devoid of any fertilization (CONTROL), a conventional treatment comprising NPK fertilization (NPK), a treatment incorporating 5 % biofertilizer (5BIO), a treatment incorporating 15 % biofertilizer (15BIO), and a treatment incorporating 25 % biofertilizer (25BIO). At the 90-day mark, the NPK treatment exhibited the greatest plant height (272.81 cm), while at the 108-day interval, the cob insertion height (170.40 cm) was also the highest. However, the 25BIO treatment yielded the most optimal results in terms of cob length (14.29 cm), diameter (6.07 cm), 1,000-grain weight (31.70 g), and yield (9 t.ha^-1). This treatment also demonstrated the highest net benefit ($2,019.10) and favorable profitability (72 %) compared to the other treatments. The results of the orthogonal contrast analysis indicate that there are significant linear effects for the majority of variables, with no discernible quadratic effects. This evidence substantiates the potential of biofertilizers in enhancing maize crop productivity. By repurposing organic waste from the agricultural sector and employing it as an alternative to chemical fertilizers, these findings contribute to the advancement of more sustainable and profitable agricultural practices.

Phenotypic and symbiotic characterization of bacteria nodulating Genista saharae in the arid region of Algeria

Manel Djouama — 2024-11-04

Twenty bacterial strains had been isolated from root nodules of Genista saharae that grew wild in Biskra and El Oued city (Northeastern Algerian Sahara). This study focused on obtaining isolates of legume nodule bacteria (LNB) from the plant G. saharae and evaluated their effectiveness in forming a symbiotic relationship with the legume species Vigna unguiculata through cross-inoculation. Additionally, the study aimed to identify the successful cross-inoculation group of LNB strains based on their phenotypic characteristics. The growth capacity of isolates under varying salinity conditions [NaCl] and pH levels was investigated using a spectrophotometer (96-microplate reader). The API 20NE and API 20E systems were used to identify the biochemical characteristics of the isolates. In addition, the rhizospheric soil samples from the two study sites were analyzed using standard analytical techniques of soil. All isolates established effective symbioses with Vigna unguiculata, were Gram-negative rods, and were fast-growing. The optimal growth temperature was between 28 °C and 37 °C; some isolates were thermophiles and specifically withstood extreme heat between 45-50 °C. Furthermore, they demonstrated a wide tolerance range to pH (5–10) with salt tolerance ranging from 100 mM to 500 mM. Biochemical results revealed that the isolates assimilated various sources of carbon and nitrogen and displayed numerous enzyme activities. Physicochemical analysis revealed that all the soils were deficient in nutrients and had an alkaline pH. This study enabled us to identify the effective stress-tolerant strains, which could be used in the future to inoculate plants for environmental applications.

Diversity variability of native corn cobs in the high zone of Totonacapan, mesoamerica

Isabel Alemán-Chávez — 2024-11-18

Mexico is considered one of the origins of corn (Zea mays L.), and in the Totonacapan area there are still native plant genetic resources that have not been characterized and are under threat by the introduction of improved genetic material and/or commercial seeds in traditional production systems. It was evaluatedthe morphological variability of native corn in the municipalities of Coahuitlán, Mecatlán and Filomeno Mata from the Totonacapan region. The experimental design implemented was non-balanced hierarchical, and principal component and correspondence analysis were also developed; six producers were visited per community within each municipality. The corn from Filomeno Mata was characterized by thick cobs, long leaves (totomoxtle) and large ears, while those from Coahuitlán and Mecatlán converge in heavy cobs with many long and heavy grains per row. The characteristics of the municipalities define the agricultural practices of the producers. Finally, significant differences (P ≤ 0.001) were found in the length, perimeter and coverage of the leaf, cob, and grain between producers from different municipalities and from the same municipality. The morphological diversity of native corn between producers from different communities is fostered by differences in the productive practices they employ within each municipality.

Biosolubilization of phosphate by strains of Trichoderma in vitro and in greenhouse in three varieties of Coffea arabica

Rosa Arias — 2024-11-18

Coffee soils have a low availability of phosphorus, the use of phosphate-solubilizing Trichoderma strains is a promising sustainable strategy for the management of phosphorus deficiencies. In this study in Mexico, we evaluated 10 strains of Trichoderma from the andosol soil of coffee plantations in Mexico and their capacity for phosphate solubilization in vitro, and their impact on the growth of coffee seedlings of three varieties (Anacafé, Costa Rica and Marsellesa) were evaluated. The tested microorganisms showed high phosphorus solubilization, the phosphorus solubilization ranged between 2.41 and 7.40 mg.mL^-1. The maximum phosphate solubilizing activity was observed using two strains of Trichoderma harzianum 75.73 (Th53) and 74.62 mg.mL^-1(Th48) for calcium phosphate (Ca₂PO₄) and three strains of T. asperellum 22.99 (Th57), 22.90 (Th49) and 21.55 mg.mL^-1 (Th40) for aluminum phosphate (AlPO₄). In both calcium (Ca₂PO₄) and aluminum phosphate (AlPO₄), a decrease in the pH of the medium was detected, from 4.81 to 3.73 and from 3.38 to 2.75, respectively. In the Anacafé variety, the application of two strains of T. harzianum (Th48 and Th53) favored greater availability of phosphorus in the substrate, while in the Costa Rica and Marsellesa varieties the available phosphorus of the substrate was greater with T. harzianum (Th48). Inoculation with these Trichoderma strains is potentially important for the solubilization of insoluble phosphorus and the development of coffee plants.

Digestible energy and nutrient digestibility of full-fat soybean meal in adult and growing guinea pigs

Celia Chillpa-Sencia — 2024-09-26

The use of full-fat soybean meal (FSBM) in feeding guinea pigs would be a good alternative to improve dietary protein, but little is known about the use of their nutrients in this animal species. This study aimed to determine the nutrient digestibility and energy digestible of FSBM and the effects of its incorporation in guinea pigs' diets. Thirty male guinea pigs were used, aged two (15 animals) and 10 weeks (15 animals). A basal diet was used, from which the weight/weight substitution was carried out at proportions of 15 and 30 % inclusion of FSBM. The digestibility of nutrients in the diets differed between ages, being higher in adults than in growing (p<0.001). The digestibility of DM and nutrients of FSBM was high, being higher in adult guinea pigs (76.94 % DM, 77.56 % OM, 82.34 % CP, 86.87 % EE, and 60.96 % CF) than growing (71.78 % DM, 72.35 % OM, 66.24 % CP, 60.37 % EE and 50.41 % CF) (p<0.001). The digestible energy was 3375 and 3093 kcal.kg^-1 DM for adult and growing guinea pigs respectively (p<0.001). FSBM meal is a good option for feeding growing and adult guinea pigs due to its high nutritional value and digestibility.

Gums exudates of Prosopis spp. located in Ecuador: prebiotic potential in animal feed

Fernando Rincón-Acosta — 2024-11-04

Fiber-rich plant foods have been tested as prebiotics (adjuvant to the growth and activity of the gut microbiota) in animal production, due to their high inulin and fiber content, in order to reduce the use of antibiotics and microbial resistance. The gummy exudate produced by Acacia senegal is a source of nutritional fiber that has been tested as a prebiotic in animal feed. The objective of this study was to analyze the potential use of novel sources of Prosopis spp. gummy exudates as prebiotics in animals of zootechnical interest based on a systematic literature review in indexed journals of the use of gum-hydrocolloids as an alternative supplement in animal feed. The scientific articles reviewed show the benefits of using the gummy exudate of Acacia senegal as a prebiotic in the production of broilers, turkeys, rabbits, and pigs. The gums obtained from Prosopis spp. present physicochemical and nutritional characteristics analogous to those published for gum arabic. Therefore, based on the bibliographic reports consulted, the gummy exudate obtained from Prosopis spp trees located in Ecuador could present a nutritional profile with excellent fiber content, oligosaccharides, essential minerals, and phenolic compounds, which would enhance its use as a promising prebiotic in animal feed, improving the function of the intestinal barrier, favoring the growth of beneficial microbiota, significantly reducing the populations of pathogenic bacteria, optimizing animal welfare and production.