Agro Productividad

Effect of branch girdling on the alternate bearing, yield, and fruit quality of grapefruit (Citrus paradisi Macf.)

Héctor Rojas-Pérez — 2024-12-04

Objective: The objective of this research was to evaluate the effect of girdling branches, application of gibberellic acid (GA₃), and foliar urea on the alternating yield and quality of grapefruit (Citrus paradisi Macf) fruits.

Design/methodology/approach: The experiment was carried out on trees during abundant harvest (“on” year) and trees with low harvest (“off” year). Foliar applications of GA₃ and foliar urea were performed with a manual sprayer at a rate of 7 L tree^-1 of solution. Branch girdling (5.0 mm wide) was performed on two-thirds of the secondary branches using a circular-edged knife to avoid damaging the xylem. The experimental design was completely randomized, with 2⁴ factorial arrangements with 16 treatments and 3 repetitions. Each experimental unit was a tree to evaluate fruit yield and quality at the experiment's conclusion.

Results: Branch girdling increased the diameter, the number of fruits, the yield, and the ºBrix-Acidity ratio of the juice. Foliar urea applications increased the percentage of juice but delayed ripening. The combination of branch girdling plus foliar urea applications increased fruit weight. The yield increase was attributed to the number of fruits rather than their weight. The treatments did not reduce alternate bearing.

Limitations on study/implications: The commercial cultivation areas for the experiment were limited due to the availability of facilities for testing fruit quality.

Findings/conclusions: To increase the size and number of fruits, with an increase in yield, branch girdling is an effective option. Furthermore, the application of foliar urea increases the percentage of juice and fruit weight, with a slight delay in maduration. However, the treatments did not reduce alternate bearing. Future research is required with other grapefruit varieties at different application times.

Effectiveness of Chemical Fungicides for the in vitro Control of Fusarium spp. Causing Basal Rot in Onion in Sinaloa, Mexico.

María A. Payán-Arzapalo — 2024-12-04

Objective: Identificar la efectividad in vitro de cinco fungicidas químicos, y el porcentaje de inhibición de crecimiento micelial de F. falciforme, F. brachygibbosum y F. oxysporum en la producción de cebolla.

Design/methodology/approach: Los aislamientos se sometieron a una prueba de sensibilidad in vitro de cinco fungicidas con concentraciones de 1, 10, 100 y 1000 ppm en medio de cultivo PDA. Se transfirieron discos de 0.5 cm de diámetro de los aislamientos al centro de caja Petri que contenían el medio de cultivo impregnado con los fungicidas. Se estableció un diseño completamente al azar con cinco tratamientos y un testigo, con tres repeticiones por concentración. Se midió el crecimiento micelial y se calculó el porcentaje de inhibición de crecimiento micelial.

Results: Se observó diferencia en el porcentaje de inhibición del micelio entre los fungicidas y las especies siendo tubeconazole el más efectivo. Además, se encontró que, a mayor dosis de fungicida, el porcentaje de inhibición micelial disminuye. El fungicida más efectivo para F. falciforme y F. brachygibbosum fue boscalid y verango a bajas concentraciones, y tubeconazole y tiabendazol a altas concentraciones. Para F. oxysporum boscalid y verango fueron más efectivos a bajas concentraciones.

Findings/conclusions: En general, F. oxysporum mostró una mayor sensibilidad a todos los fungicidas.

Endophytic Mycorrhiza-mediated Phytogen resistance in plants

Juan A. Espinoza-Alonso — 2024-12-04

Objective: Mycorrhizal fungi are a group of microorganisms that live insithusants, thus, maintaining perceptible associations with their host plants in certain parts of their life cycle. They can be characterized by their capacity to synthesize secondary metabolites and to promote growth and induce plant-disease resistance, therefore, gaining greater biotechnological importance in pest and diseases management for crops of agricultural relevance. The study of these microorganisms has been a widely researched area subject for more than half a century. Design/methodology/approach: Their biology and molecular relationships in plant-microorganism interactions, on the other hand, have only recently begun to gain relevance for understanding the colonization process in recent decades. There has been observed a complexity in the generation of formulations that can guarantee the permanence of fungi outside the host plant. Findings/conclusions: This review article will address topics related to their biology, ecological role, possible negative effects on commercially important animals, and successful cases in Mexico regarding biotechnological products based on these microorganisms.

Effect of saline concentrations and humidity percentage on alfalfa va-rieties (Medicago sativa L.) from the Mexicali Valley, Mexico.

S. Caballero-Julián — 2024-12-04

Objective: The aim of this experiment was to identify alfalfa varieties resistant to salt and drought stress in Mexicali Valley Mexico.

Design/methodology/approach: Four alfalfa (M. sativa L.) varieties were used: Cuf-101 C, FD9, Pioneer and Cuf-101 P. Drought stress resistance was evaluated using four different percentages of commercial peat moss substrate (100%, 50%, 25%, and 15%), and saline stress resistance was evaluated by applying four concentrations of NaCl (0 mM, 50 mM, 100 mM, and 200 Mm.The variables evaluated in each treatment were: plant height, number of leaves and root length. The data obtained were subjected to an analysis of variance using the SAS statistical package version 9.0 with an α=0.5.

Results: Alfalfa variety Cuf-101 had a good adaptation to both stresses with an average height of 11.28 cm and an average number of leaves of 3.54. Seed germination of alfalfa varieties (M. sativa L.) subjected to salt stress were affected even at the lowest NaCl concentration.

Conclusions: The alfalfa variety with the highest germination percentage in all NaCl concentrations was Cuf-101 C with 91.17%.