La marchitez por Fusarium causada por Fusarium oxysporum f. sp. lycopersici (Fol) es una de las enfermedades más importantes del cultivo del tomate (Solanum lycopersicum L.). Su variabilidad patogénica ha originado las razas 1, 2 y 3, ya descritas en varios países. En México se ha reportado en Sinaloa, Baja California Sur y Morelos. El tomate es un cultivo hortícola muy importante en Villa de Arista, San Luis Potosí, por lo que el objetivo de este trabajo fue caracterizar mediante pruebas de patogenicidad la variabilidad en la virulencia de aislamientos de Fol en predios tomateros de esta región. Se obtuvieron 27 aislamientos de Fusarium oxysporum de plantas de tomate con síntomas característicos de la marchitez por Fusarium de nueve variedades en siete predios tomateros, las cuales se procesaron en laboratorio para aislar el hongo, purif icarlo, preparar inoculo y realizar pruebas de patogenicidad. Las variedades diferenciales utilizadas fueron Bonny Best, susceptible a las razas 1, 2 y 3; Manapal, resistente a la raza 1; Walter, resistente a las razas 1 y 2; e I3R3, resistente a las razas 1, 2 y 3. Las razas identificadas fueron, raza 2 en las variedades Rafaello y Tipsey en los predios Agro Viva y Rancho el Clérigo, y la raza 3 en las variedades El Cid, Aníbal y 77-05 en los predios San Gilberto, Santa María Elena yLourdes.Laidentificacióndeestasrazasmediantelatécnica molecular de la Reacción en Cadena de la Polimerasa (PCR) coincidió con los resultados de las pruebas patogénicas.

Objective: To identify optimal sowing ratios, validation of production technology and seed quality in maize hybrids. Design/methodology/approach: Sowing ratios of 4:2 and 6:2 were studied to observe their effect on the genotypes, as well as their quality and response in seed production; this was done by evaluating the following variables: days to male and female flowering, plant and ear height, percentage of ear and seed in cobs, commercial seed yield, thousand seed weight, number of seeds per kilogram, standard germination and hectoliter weight of the seed. An analysis of variance was carried out using a completely randomized design with factorial arrangement and four replications, the experimental unit being furrows of 20 linear meters. Results: Significant differences were detected in the hybrids with respect to the variables and sowing ratios, which specifically influences the weight, size and number of seeds; the hybrid H-386A had the best response to the environment and ratios, exceeding the rest of the hybrids evaluated by 72.92 %. Limitations on study/implications: The interaction of genotype and environment are factors that limit seed production; however, performing evaluations in different environments allows finding stable hybrids with high yields. Findings/conclusions: The generation of knowledge allows us to make decisions regarding crop establishment and quality in seed production lots, being a recommended environment in CIRPAC’s area of influence

Aims: To estimate the effects of general and specific combinatorial fitness in parents and progeny on yield and fruit quality related traits of melon. Study Design: A completely randomized block design with three replications was used to estimate the analysis of variance and the effects of general combining ability (GCA) and specific combining ability (SCA). The genetic analysis was carried out based on the Griffing Method II dialelic design (1956) with fixed effects model. Tukey P=.05 mean comparison analysis. Place and Duration of Study: The research was conducted in two stages. In stage 1, seed production of the parents and crosses was carried out at the Physiotechnical Greenhouse of the of the Universidad Autónoma Agraria Antonio Narro, Saltillo, Coahuila. Mexico, between April and July 2021. In stage 2, the evaluation of the parents and progeny was carried out between August and November 2021 in the agricultural field "La Jaroza", Paila, Coahuila. México. Methodology: In the present study, seven melon parents were analyzed. The parents were crossed in all possible combinations, without reciprocal crosses, resulting in 21 progenies, a total of 28 genotypes evaluated. Results: The results showed significant differences between genotypes, general and specific combining ability effects (GCA and SCA) for almost all variables, except fruit number. The parent "(E x L)" showed the best yield and GCA effects, and participated in most of the outstanding crosses in yield, average fruit weight, fruit length, fruit width, flesh thickness, seed cavity and soluble solids. The "N x (E x L)" progeny excelled in yield and average fruit weight in SCA. Conclusion: The parent "(E x L)" showed the best yield and GCA effects and participated in most of the outstanding crosses in yield, average fruit weight, fruit length, fruit width, flesh thickness, seed cavity and soluble solids. The progeny "N x (E x L)" excelled in yield in SCA.

El tomate es una de las hortalizas de mayor consumo a nivel mundial tanto en fresco como en procesos industriales. Sin embargo, en México los rendimientos en campo abierto e invernadero son generalmente bajos. Para incrementar el rendimiento es necesario, entre otras acciones, realizar evaluaciones respecto a los efectos genéticos en variedades e híbridos. El objetivo de este estudio fue determinar los efectos genéticos e identif icar genotipos con potencial de rendimiento en ocho variedades de tomate (Solanum lycopersicum L.) y sus 28 híbridos F1. Las cruzas se produjeron en un invernadero de la Universidad Autónoma Agraria Antonio Narro (UAAAN) en Saltillo, Coahuila, México, durante el ciclo (O-I 2011) y se evaluaron en un lote experimental de la misma universidad en el ciclo (P-V 2012), bajo un diseño experimental de bloques completos al azar, con tres repeticiones. Se observó significancia (p≤ 0.01 y p≤ 0.05), en las fuentes de variación de genotipos, variedades, heterosis, heterosis promedio, heterosis varietal y heterosis especifica en la mayoría de las variables en estudio. Las variedades IR9 e IR13 mostraron el mayor efecto de ACG y los híbridos IR14*D6, IR13*D4 y D4*D3 presentaron altos valores de ACE para rendimiento y por consecuencia los mayores rendimientos, superando los 100 t ha-1 en campo abierto. Las variedades y cruzas con mayores efectos aditivos (ACG) y no-aditivos (ACE) con respecto a rendimiento, podrían ser usadas dentro de un programa de mejoramiento genético, donde la acción aditiva puede ser manejada bajo un esquema de selección recurrente y la no-aditiva por hibridación.

a) Objective. The objective was to evaluate the forage production of maize, maize + sunflower and its preference for sheep as silage. b) Design/methodology/approach. The design in the field was in completely randomized blocks with three replications and in the laboratory in a completely randomized design (Tukey α = 0.05). Sowing was in spring - summer 2020 under rainfed conditions. The treatments were: 100 % corn, 90 % corn + 10 % sunflower, 80 % corn + 20 % sunflower. Forage production was evaluated at 126 days of sowing, it was ensiled and the quality through bromatological analysis. For silage preference, 10 pregnant Hampshire × Suffolk ewes were used with 44.8 kg of live weight along 20 days. c) Results. The 80 % maize + 20% sunflower combination showed higher green forage yield (P<0.001; 28 t ha-1), higher percentage of soluble protein (P<0.01) and higher percentage of lignin (P<0.001; 4.6 %). The sheep preferred the silage with 100 % corn, since it had a lower percentage of non-fibrous carbohydrates (22.2 %), lower acid detergent fiber (35.3 %) and lower neutral detergent fiber (59.4 %). d) Limitations/implications. Sunflower should be established on soils with low numbers of broadleaf plant seeds, because chemical control cannot be applied. e) Findings/conclusions. A greater amount of forage was produced per surface unit whit 80 % corn + 20 % sunflower. The 100 % maize silage was preferred by sheep due to lower percentage of lignin, and higher in vitro digestibility of neutral detergent fiber.