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

Objective: Evaluate the White-tailed Deer (WTD) in vitro embryo production (IVP) and oocytes vitrified with Trehalose (TH) or Sucrose (SC). Design/methodology/approach: Total vitrified oocytes were placed into two different groups: TH (n=60) and SC (n=61). Samples were selected and analyzed for viability evaluation TH (n=5) and SC (n=5), nuclear status (NS) TH (n=4) and SC (n=5), Germinal Vesicle (GV), Metaphase I, or not evaluable (NE) after warming. In vitro maturation (IVM) was conducted for 36 h in supplemented TCM-199 medium. Immediately afterwards, oocyte NS was evaluated (n=88) [(GV, MI=immature), (MII=mature)]. In vitro fertilization (IVF) was performed in supplemented TALP medium for 24 h using frozen WTD semen (3x106 sperm/mL), NS was classified [Fertilized (F), Not fertilized (NF), or NE]. Results: After warming, viability for the TH group (n=5) was 60% versus 40% for SC group (n=5), however, oocytes in both groups were immature (GV and MI stage). For IVM, NS evaluations of the TH group (n=38) revealed no maturation versus 2% in the SC group (n=50) (MII stage=matured). IVF evaluations for the TH group (n=10) revealed no fertilization compared to 20% in the SC group (n=5). A statistical difference (p>0.05) was not found between the TH and SC groups. Limitations on study/implications: White-tailed Deer in vitro embryo production is not well documented. Findings/conclusions: Future research with a larger number of WTD oocytes is needed for further evaluation of oocyte vitrification IVP techniques as a model for endangered cervids.

Objective: Morphometric evaluation, weight, viability and germination under two conditions of temperature and relative humidity in sixteen local varieties of castor beans (Ricinus communis) from various states of Mexico (E1-E16) including two commercial varieties (k75B and k93B) were analyzed. Design/methodology/approach: The morphometric characteristics were: area, Elongation Index (IE) and Feret's diameter (DF), by means of a vision system. The viability and germination tolerance (germination percentage (% germination), germination speed (VG) and emergence speed index (IVE)), were evaluated under two conditions of relative humidity and temperature (T1- HR 80%/T20ºC ; T2- HR 30%/T40ºC), under a randomized complete block experiment design with four replicates of 75 seeds. Results: There are morphometric differences (IE, area and DF) between and within the study varieties. There is a significant difference between T1 and T2 in days of radicle emergence (11.6 in T2 and 44.71 in T1), germination percentage (T1: 48.37 and T2: 56%), IVE (T1:34.07+12.72 and T2: 77.02+ 23.78) and VG (T1: 9.93 and T2: 24.60). The results obtained show that there is a positive correlation between the morphometric properties and the germination percentage under T1; but in T2 no correlation was observed. The Limitations on study/implications: The study did not imply limitations. Findings/conclusions: Two local varieties E4 and E15 with productive potential higher than 93% under T1 were found; and under T2 the local varieties E3 and E16 with a productive potential greater than 78%, with respect to the commercial variety k75B showed a better performance under T1 (89.75%) than under T2 (78.67%).

Objective: To evaluate the leaf application of silicon (Si) and titanium (Ti) in three doses (0, 75, and 150 mg L-1), independently, on tomato plants cv. Río Supremo, subjected to saline stress (0, 50, and 100 mM NaCl), on the percentage of juice and color attributes of the fruit. Design/methodology/approach: Two independent essays were carried out under a completely randomized experimental design in a 32 factorial arrangement, where the first study factor was the NaCl concentration in the nutrient solution and the second factor was the leaf application of Si or Ti. The percentage of juice and color attributes in fruits were determined. An analysis of variance and the comparison of means by Tukey (p ≤ 0.05) with the SAS software were performed. Results: Salinity was found to reduce the percentage of juice, the color index, and the ratio of “a/b” indexes. Regarding the interactive effects, NaCl with both Ti and Si increases the “b” index. Leaf applications of Si increased the “b” index and reduced the percentage of juice, the color index, and the ratio of “a/b” indexes. Also, Ti improved the color index and the “b” index. Limitations of the study/implications: The results were obtained in the Río Supremo tomato variety under greenhouse conditions. Other varieties should be tested too. Findings/conclusions: Si and Ti applied to the leaves have positive effects on the color of the fruits of tomato plants under saline stress.

Objective: To characterize the understory species associated with a pine-oak forest in the Sierra Mariscal region, Chiapas. Design/methodology/approach: Six 40 m2 subplots were established to evaluate the cover, abundance and identity of shrub, herbaceous and sapling components of the understory. Floristic diversity was determined. The level of disturbance was evaluated using the observation method. An analysis of variance and comparison of means by Tukey (p<0.05) between structural variables was applied. The relationship between disturbance levels and study sites was performed by correspondence analysis. Results: The understory is composed of five tree species, three herbaceous and two shrub species. The largest diameter (p≤0.0001 and F=27.6) corresponds to herbaceous Cortaderia seolloana (5.38±0.94 cm) and Petiridium aquilinum (4.5±0.96 cm). The greatest height corresponds to Quercus sp. saplings (126.3±75.9 cm) and the herbaceous Cenchurus sp. (110.2±54.1 cm) and Peteridium aquilinum (91.7±40.9 cm), the latter having the highest density (4050 ind. ha-1) and cover (16.2%). Floristic diversity was low in all six sites. Site six was the most diverse and site three the most disturbed. Study limitations/implications: The study comprised a limited and insufficient area to generalize the conditions of pine-oak forests in the Chiapas highlands. It is suggested to expand the study universe and increase the number of replications. Findings/conclusions: Variability in understory structure and composition was found that corroborates the relationship between forest diversity and disturbance.

Objective: To estimate the median lethal dose (LD50) and mean reductive dose (GR50) due to gamma radiation in Arachis pintoi var. Amarillo seeds. Design/methodology/approach: Ten doses were used (100, 200, 300, 400, 500, 600, 700, 800, 900 and 1000 Gy) plus a control (without radiation). The experimental design was completely random with three replications and 50 seeds per repetition. Seed germination was evaluated 29 days after sowing (das) and plant survival, plant height, root length and leaf area at 60 das. The LD50 and GR50 for survival and plants height were estimated by linear regression. Results: There was a significant reduction of seed germination and plant survival from 300 and 200 Gy doses compared to the control (61.64 and 49.15 % each); for the plants height the dose was of 100 Gy (35.22 %). There were no differences in the root length and leaf area with 100 and 200 Gy regard to the control. The LD50 was estimated at 212.54 Gy and the GR50 at 162.16 Gy. Findings/conclusions: The gamma radiation doses to induce genetic variation in A. pintoi var. Amarillo seeds were between 162 and 212 Gy.

Objective: in this research, we assessed the level of organic inputs usage in contrast to chemical inputs in sugarcane producers at the ejido Jareros, Veracruz, in the municipality of Ursulo Galvan. Design/methodology/approach: Through surveys, a descriptive statistical analysis was conducted on the main socioeconomic aspects of the sugarcane producers in the ejido and an analysis of the means significance of the level of usage of agricultural inputs (chemical / organic) divided into five variables: pesticides, fungicides, acaricides, fertilizers and weed control. Results: The significance value of the five variables analyzed was: pesticides (p=0.1774); fungicides (P = 0.2090); acaricides (0.3625); fertilizers (P = 0.0005) and weed control (P = 1.0000). Limitations on study/implications: Findings/conclusions: Based on the significance values and mean difference of the five assessed variables, it is concluded that the excessive use of nitrogenous fertilizers is the factor with the greatest potential to negatively impact the environmental and edaphic deterioration of arable soils in the Jareros ejido, State of Veracruz, Mexico.

Objective: To analyze the possibilities and actions required to foster the introduction of technologies consistent with the term “agriculture 4.0” in Mexico.Design/Methodology/Approach: To identify providers of technology in Mexico. To present the cost-benefit equation regarding the adoption of said technology as applied to the cultivation of maize in different regions. Todesign and construct an adoption propensity index that will serve as a basis to propose focused and adequate actions to remove technology access barriers.Results: Mexico has a young and wide offer of technology, both tangible and intangible, where digital platforms of agricultural management, mobile apps, and remote monitoring predominate. The cost-benefit relationshipoffers a large margin to adopt new technologies. However, there are adoption barriers (related to education or infrastructure, for instance) that represent a challenge to different regions of the country: the northern,northeastern, and western states of Mexico are more likely to adopt new technologies.Study limitations/Implications: Further experimental and field analysesare required to delve deeper into potential additional barriers (culture-related, for example). Agro productividad 2022. https://doi.org/10.32854/xxxxxx (Los autores no deben realizar ningún cambio en este apartado) 2 of 8 Findings/Conclusions: The cost-benefit analysis offers a large margin foradoption. However, the propensity to adopt is associated to restrictingfactors such as the producers’ educational level, the production unit’s sizeand level of mechanization, the access to and use of Information andCommunication Technologies, and the telecoms infrastructure, whosegeographic disparity is significant. The public sector’s intervention isdesirable to reduce the gap between the supply and demand oftechnologies, as well as the access barriers to the latter.

Objective: To describe the function of Fec, CA5A and CLSTN2 genes during ovulation in ewes. Design/methodology/approach: A search and analysis of scientific information related to Fec, CA5A and CLSTN2 genes in sheep was performed. Results: Fec, CA5A and CLSTN2 genes are involved at the ovarian level; ewes carrying the first gene were found to have increased ovulation rate, folliculogenesis and granulosa cell differentiation. CA5A stimulates an increased follicular rate and plays an important role in pre-implantation. While CLSTN2 has activity in ovarian development and growth; it also has the ability to interact with other genes involved in follicular maturation, granulosa cell differentiation and development of the ovarian follicle. Limitations on study/implications: Ewes carrying these genes increase the prolificacy rate in the flock. Findings/conclusions: The expression of these genes acts synergistically in the ovulatory process, enhancing the ovulatory response by contributing to endocrine, paracrine and molecular synchronisation, so that the maturation of the oocyte occurs, leading to ovulation.

Objective: To explore the available literature relating to lethal yellowing (LY) in order to assess the susceptibility of royal palms (Roystonea spp.) to this disease. Design/methodology/approach: Bibliographic material in English and Spanish was consulted in physical and digital libraries in search of unequivocal and/or plausible LY reports in Roystonea palms. Information gathered was then reviewed and discussed. Results: We found evidence of LY susceptibility of royal palms dating back to the beginning of the 20th century. In addition to Mexico, possible LY outbreaks in Roystonea palms might have occurred in Cuba, Haiti, the Dominican Republic, and Antigua and Barbuda. Limitations on study/implications: Reports of LY predating molecular diagnostic tools, particularly in Roystonea palms, cannot be assumed as unequivocal evidence of susceptibility to this disease. Findings/conclusions: Royal palms have shown evidence of susceptibility to LY throughout the Caribbean Basin. In light of this, their potential role as phytoplasma reservoirs should be examined in order to better comprehend this disease’s pathosystem.

ABSTRACT Objective: To describe the pollination syndromes of the orchids of Megamexico and the importance of the interactions between the orchids and their respective pollinators for the conservation of both groups. Design/Methodology/Approach: An exhaustive search was carried out on the pollinators of each of the orchids that grow in Megamexico. With the information sources available, a data matrix was prepared that includes orchids and all their pollinators. Subsequently, it was quantified which group of pollinators the orchids interact with the most. Finally, it is described what physiological adaptations and morphologies orchids have developed to attract specific pollinators. Results: Orchids from Megamexico maintain close relationships with specific pollinators. Said interaction is mediated by the shape, size, production of aromas, nectar, and the color of the flower. Thus, four large groups of pollinators are those that interact with the orchids of Megamexico, with the Hymenoptera being the group of pollinators that pollinates the most orchid species in Megamexico and birds to a lesser extent. Study Limitations/Implications: This study describes the importance of pollinators and their interactions with orchids for orchid prevalence. Findings/Conclusions: It is of vital importance to include orchid pollinators in conservation programs to ensure that interactions between orchids and pollinators continue to be effective and thus guarantee the permanence of the two groups.