Aaron Isain Melendres-Alvarez’s research while affiliated with Universidad Autónoma Agraria Antonio Narro and other places

La frambuesa es una frutilla de gran demanda en el mercado internacional. Su principal atractivo radica en el alto contenido en vitaminas A y C, fibra, nutrientes como Ca y Fe, flavonoides y antioxidantes. Estos compuestos, además de ser integrantes en su aroma y sabor, contribuyen a fortalecer el sistema inmunológico del ser humano contra enfermedades como el cáncer, diabetes y cardiovasculares. Las hormonas endógenas influyen en el rol de esas moléculas durante el crecimiento en varias especies hortícolas. En frambuesa es desconocido la presencia de hormonas naturales en el fruto. Por ello, se investigó su presencia en frutos de frambuesa cv UANC-2022, utilizando la técnica de cromatografía de gases y espectrometría de masas con un diseño completamente al azar. Se identificaron las giberelinas A4, A7, A44 y A53; auxina ácido indol acético y la citocinina zeatina.

Background Adult pecan trees require a significant water supply for high yields and nut quality. Pecan nut orchards are established in semi-arid regions where water is the primary limiting resource for agriculture. Therefore, in these regions, improving water use efficiency is essential. Objective Evaluate the water use efficiency of a pecan tree orchard based on the comparison of irrigation scheduling with the evapotranspiration rate data. Methods The study was conducted in a pecan nut (Carya illinoinensis) orchard of 7.2 ha with 7-year-old Western and Wichita cv tress. The volume of water applied to each tree (drip irrigation) was converted to a daily irrigation depth and compared against the daily rate of actual (measured with an Eddy covariance system) and the FAO Penman-Monteith evapotranspiration. Results Comparing the monthly water depth applied to each tree against the monthly FAO-Penman Monteith ET, surplus or deficit irrigation episodes were detected. Because the canopy trees only covered 18.7% of the orchard area, the daily rate of actual evapotranspiration during the months of the trees growing was very small (1 to 2 mm) compared with the orchards of mature pecan trees. The corresponding monthly crop coefficients (Kc) were also small (0.315 on average). Conclusion This study showed that by comparing the rate of ETref against the irrigation depth applied to the trees in the irrigation scheduling, it is possible to reveal cases of surplus or deficit of water supplied to a pecan nut orchard.

Aims: Habanero pepper (Capsicum annuum L.) cultivation is growing worldwide, mainly as a result of its high demand and nutritive contribution to human society. The presence of endogenous gibberellins and cytokinins in seeds of various vegetable crops has been related to a good germination; however, little is known on habanero pepper. The aim of this study was to search for the presence, identification and amount of gibberellins and cytokinins in seeds of habanero pepper cv "Jaguar". Study design: Laboratory analysis for gibberellins and cytokinins were organized in solvent solutions groups with three technical replicates using a complete randomized design and results when applicable were analyzed using the statistical program 'RStudio' (version 10) and data Original Research Article Ramírez et al.; IJPSS, 33(12): 9-18, 2021; Article no.IJPSS.68936 10 obtained subjected to a comparison of means with the Tukey (P≤0.05) test. Place and duration of study: The experiment was conducted at the Department of Horticulture in Universidad Autónoma Agraria Antonio Narro, Saltillo, Mexico, during 2020-2021. Methodology: Lots of 50 grams dry weight of "Jaguar" habanero pepper seed samples were freeze dried and prepared with several organic solvents for the extraction, purification and identification of gibberellins and cytokinins using the techniques of GC-MS and GCMS-SIM respectively. Results: Gibberellins A 1 , A 4 , A 7 , A 9 , A 15 , A 17 and A 44 were found in habanero seed tissue. The cytokinins zeatin and zeatin-riboside were also detected in analyzed habanero samples. Conclusion: The endogenous gibberellins A 1 , A 4 , A 7 , A 9 , A 15 , A 17, A 44 , and the cytokinins zeatin and zeatin-riboside are present in habanero pepper cv "Jaguar" contributing to an improve seed viability, ensuring health and overall plant yield.

Aims: Tomato (SolanumlycopersicumL.) is one of the most important vegetable crops worldwide, mainly as a result of its economic and nutritive contribution to human society. The presence of endogenous gibberellins and cytokinins in seeds of several crops has been related to a good germination; however, little is known in tomato. Therefore, the aim of this study was to analyze and identify the presence of gibberellins and cytokinins in saladette tomato seeds. Study Design: Laboratory analysis for gibberellins and cytokinins were conducted in solvent solutions groups with three technical replicates using a complete randomized design and results when applicable were analyzed using the statistical program 'RStudio' (version 10) and data obtained subjected to a comparison of means with the Tukey (P≤0.05) test. Place and Duration of Study: The experiment was conducted at the Department of Horticulture in Universidad AutónomaAgraria Antonio Narro, Saltillo, Mexico, during 2020-2021. Methodology: Lots of 50 grams dry weight of saladette “SVTE8832” tomato seed samples were freeze dried and prepared with several organic solvents for the extraction, purification and identification of gibberellins and cytokinins using the techniques of gas chromatography mass spectrometry(GC-MS) and gas chromatography mass spectrometry with selection ion monitoring(GCMS-SIM) respectively. Results: Gibberellins A1, A4, A7, A9, A12, A15, A17, A20, A44 and A53 were found in tomato seed tissue. The cytokininszeatin and zeatin-ribozide were also detected in analyzed tomato samples. Conclusion:The endogenous gibberellins A1, A4, A7, A9, A12, A15, A17, A20, A44, A53 and the cytokininszeatin and zeatin-riboside are present in saladette“SVTE8832” tomato seeds.

With the purpose to search upon the cytokinins origin, a study was conducted on the effects of prohexadione-ca (P-Ca) on cytokinins in xylem sap and on stomatal resistance in apple. Golden Delicious seedlings were sprayed with 100 ppm P-Ca. Stomatal leaf resistance was measured at intervals between 1 and 4 hours of spraying and 15 days after the treatment. Golden Delicious trees were sprayed with 200 ppm P-Ca two weeks after full bloom. At intervals between 1 and two weeks after P-Ca treatment, the main de-shooted stem was removed from root system and xylem sap was collected for cytokinins analysis using the suction technique. Prohexadioneca significantly increased stomatal resistance (range 2.74-4.35 s/cm−1) when compared to control (range 2.12-3.44 s/cm−1); however, P-Ca did not modify the level of cytokinins in xylem sap since range values were between 0.10 to 0.20 μg kinetin equivalents/20 ml xylem sap for both, cytokinin and control.

Aims: The apricot (Prunus armeniaca L.), is a drought-sensitive deciduous fruit. This concept arises from the fact that soil moisture stress can: Decrease the number and quality of flower buds differentiated; delay the time of flower differentiation and decrease the number of flower buds per shoot. The objectives of this investigation were to determine: The extent to which drought influences water status in the leaves; its effect on flower buds development and on bloom in apricot cv. "Royal". 11 Study Design: Trees were divided into 6 groups of six replicate each under a random block design. Results were analyzed using the statistical program 'RStudio' for Windows version 10 and data obtained subjected to a comparison of means with the Tukey (P≤0.05) test. Place and Duration of Study: The experiment was conducted at the Department of Horticulture in Universidad Autónoma Agraria Antonio Narro, Saltillo, Mexico, during 2018-2019. Methodology: Seven-year-old apricot trees growing in containers were subjected to a 4 to 5week period of water stress at different times during the growing season. Leaf water potential was periodically measured and flower bud development was followed from early differentiation up to full bloom. Results: Leaf water potential in water stressed trees was constantly low. Water stress early in the season induced a delay in bud development during late summer and fall. Water stress late in the season did not appreciably affect the rate of bud development. Full bloom was delayed when water stress was applied in late summer and fall. Water stress at flower bud initiation and differentiation, together with high temperatures, may have induced flowers with double pistils. Water stress from April through October did not induce flower drop. Conclusion: Soil water stress severely affect leaf water potential; delays flower bud development and may induce flowers with double pistils without flower drop.

The roof color of tunnels and greenhouses can modify the spectral characteristics of solar radiation and affect the development and performance of plants. The objective in this study was to evaluate the effect of the color cover of a tunnel on the magnitude and characteristics of radiation on a sweet pepper culture (Capsicum annuum L.) and its relationship with chlorophyll content, growth and yield. This study was carried out in four tunnels covered with red, blue, and translucent polycarbonate and high-density diffuse polyethylene. The spectral properties of the radiation under each cover were determined with a spectroradiometer. The radiation effects on the growth and yield of plants were evaluated in a completely random design with sub-sampling in five treatments (covered tunnels and open field), three repetitions and three samples (plants) per replicate. The Tukey test (p0.05) was used for means comparison. The photosynthetically active radiation (PAR) transmitted under each cover during the crop's growth cycle was of 79.22, 53.40, 49.52 and 23.35% for the translucent polycarbonate, high density diffused polyethylene, blue polycarbonate and red polycarbonate, respectively. The transmissivity wavelength ranging from 400 to 550 nm in the red polycarbonate was almost null. Therefore, plants under the red cover had a greater plant height and leaf area, but lower fruit yield. The highest fruit yield was under the high-density diffused polyethylene, due to its greater diffusivity and PAR penetration in the plants foliage.