Background: A modified laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was used to obtain methane by treating hydrous ethanol vinasse. Vinasses or stillage are waste materials with high organic loads, and a complex composition resulting from the process of alcohol distillation. They must initially be treated with anaerobic processes due to their high organic loads. Vinasses can be considered multipurpose waste for energy recovery and once treated they can be used in agriculture without the risk of polluting soil, underground water or crops. In this sense, treatment of vinasse combines the elimination of organic waste with the formation of methane. Biogas is considered as a promising renewable energy source. The aim of this study was to determine the optimum organic loading rate for operating a modified UASB reactor to treat vinasse generated in the production of hydrous ethanol from sugar cane molasses. Results: The study showed that chemical oxygen demand (COD) removal efficiency was 69% at an optimum organic loading rate (OLR) of 17.05 kg COD/m³-day, achieving a methane yield of 0.263 m³/kg COD_added and a biogas methane content of 84%. During this stage, effluent characterization presented lower values than the vinasse, except for potassium, sulfide and ammonia nitrogen. On the other hand, primers used to amplify the 16S-rDNA genes for the domains Archaea and Bacteria showed the presence of microorganisms which favor methane production at the optimum organic loading rate. Conclusions: The modified UASB reactor proposed in this study provided a successful treatment of the vinasse obtained from hydrous ethanol production. Methanogen groups (Methanobacteriales and Methanosarcinales) detected by PCR during operational optimum OLR of the modified UASB reactor, favored methane production.

The objective of this study was to establish an efficient—direct or indirect—regeneration system for pineapple (Ananas comosus L.) plants, with a high rate of multiplication and that would preserve the genetic identity of the donor genotype (Hybrid ‘MD2’) in the regenerated plants. Ten treatments, with different concentrations of 2,4-Dichlorophenoxyacetic (2,4-D) and Picloram (P), in the absence or presence of 6-Benzylaminopurine (BAP), were used for in vitro morphogenesis induction, as well as histological and molecular techniques, in order to characterize the morphogenic responses induced. Significant differences between treatments tested, to induce callus and buds, were assessed by the Kruskal Wallis method and the Mann–Whitney U-tests. Different pineapple regeneration routes were identified, showing the high regeneration potential of this species. The medium containing 2 mg L⁻¹ 2,4-D and 2 mg L⁻¹ BAP, where indirect somatic embryogenesis occurred, was selected as the most efficient treatment, with an average of 120 somatic embryos per explant, differing significantly from the rest of the treatments. It was also demonstrated that the pineapple plants regenerated in vitro preserved the genetic identity of the donor genotype, which represents a high degree of confidence for the application of indirect somatic embryogenesis for A. comusus clonal propagation.

El sistema tradicional milpa, manejado mayormente bajo temporal en Yucatán, México; es importante a nivel social, biológico y ambiental. La milpa ha perdurado a través del tiempo por los conocimientos ancestrales transmitidos por generaciones. Por lo anterior, el objetivo fue conocer las estrategias de manejo realizadas por los milperos en su actividad agrícola y la conservación de la diversidad biológica. La investigación se efectuó en la comunidad maya de Xoy, Peto, Yucatán aplicando encuestas semiestructuradas al 30% de la población ejidataria que siembra maíz. La diversidad de cultivos reportada en Xoy fue de 22 variedades nativas: ocho de maíz, siete de frijol lima, cuatro de calabaza y tres de frijol común. Se detectó que la familia es el determinante para la conservación de la diversidad de especies cultivadas en la milpa con una prioridad en la conservación de semillas nativas entre los milperos.

Background: Maize (Zea mays L.) is the main sustenance in the daily diet of Mexican families. As a crop, it is one of the most important in the country of Mexico, and in Yucatan state, it is grown under rainfed conditions in milpas with no mechanizable lands. In this study, an analysis of the phenotypic variability from cob collects of native maize from Yucatan state was carried out, with ethnobotanical information collected within passport data. Objectives: To introduce the genetic diversity of maize into a germplasm bank, to know the genetic diversity of native populations based on the characteristics of cob, to know its distribution, to find the potential populations in each collection area for its use in genetic improvement programs. Methodology: 66 Tuxpeños, 13 Dzit bacal, 6 Nal tel, 13 Xmejen nal, and 2 Nal xoy were collected in the southern, central, and eastern regions of the state, from January to March 2020, by sampling the four cardinal points in each community visited. A vector map of collections in Yucatan was developed and quantitative data of 13 biometric cob variables were recorded in 100 populations (crop cycles: late n=68; intermediate n=26; early n=6), a general data analysis of variance (ANOVA) and by crop cycles were made, principal component analysis (PCA), hierarchically clustered with the average linkage method and discriminant analysis were made. Qualitative data from ethnobotanical surveys with mixed questions applied to milperos at the time of collection are presented. Results: The diversity of native maize in Yucatan is made up of three main groups based on the crop cycle: late, intermediate, and early. The southern and eastern regions of Yucatan preserve greater diversity, representing 44 and 40% of the total collections, respectively. There were significant differences in all ear variables; in a late growth cycle, only the grain thickness did not show differences between populations, and in the early growth cycle the grain thickness, width, and length variables were not significant. The PCA explained 80% of the total variation, seven different groups were formed, with greater differentiation in early maize Nal tel, intermediate Xmejen nal and Dzit bacal, contrary to the Tuxpeños late maize. Ten promising populations were identified for selection in each geomorphological region: eight correspond to the southern, two to the eastern, and one to the center of Yucatan state. The main factors to select for sowing corn in the region are: white and yellow maize for yield, the resistance to weevil attack for red maize, and the perception of color and palatability in purple maize. Implications: A complete phenotypic characterization in the field is required with a special interest in red-pigmented maize. Conclusions: The interest of the milperos in conserving and sowing the different native maize are based on the color of the grain, the benefits and uses that they can obtain from them, which determine the planting area in the milpas of the different races/varieties of maize. Red grain maize is being planted in a lower area in relation to other colors. The southern and eastern geomorphological regions showed a genetic flow between them.

In this study, the variation of morphological and agronomic characters of 10 accessions of J. curcas selected from Yucatan, Mexico, and Honduras was analyzed. The characters associated with the proportions of the plants (height, number, and length of branches), the fruits (diameter and thickness), and the seeds (length, width, and volume), as well as those associated with the agronomic yield (number and yield of seeds plant^− 1), explained the greatest variation between the accessions, 40 and 24%, respectively. The CAM32 and GAGI10 accessions had the lowest vegetative proportions and the highest agronomic yield, SUCILATEBEC and B5F59P19 had the lowest proportion and low yield, B3F119P1 had the highest proportion and high oil content, but low yield; while B5F83P1 had high values of vegetative proportions, and agronomic performance. The characters with the greatest variation among the accessions were ABM (59.93%), WV (56.91%), NS plant^− 1 (57.18%), the SY plant^− 1 (55.49%), and NL (54.37%). The similarity analysis grouped the accessions that had in common the geographical origin and the magnitudes of the characters associated with the agronomic performance and with the proportions of the plants, fruits, and seeds. The present study allowed the identification of J. curcas accessions with desirable agronomic and morphological traits, such as seed yield, oil content, and plant height, which can serve as progenitors in breeding programs for this species.