Resumen: La plasticidad fenotípica permite a las plantas lidiar con ambientes heterogéneos. Capsicum annuum silvestre es un valioso recurso genético que habita en sitios que difieren en la disponibilidad de luz. Evaluamos la variación genética entre poblaciones, la plasticidad fenotípica y su variación en respuesta a tres niveles de luz (alto, 100%; medio, 50%; y bajo, 25% de luz solar) de cinco poblaciones de Capsicum annuum silvestre del noroeste de México. Las características medidas fueron: altura de la planta, diámetro del tallo, longitud de la hoja, ancho de la hoja, número de frutos por planta, número de semillas por fruto, número de semillas por planta y peso de la semilla. Las poblaciones difirieron significativamente en todas las características medidas. Todas las características mostraron un efecto significativo de los tratamientos y todas, excepto el diámetro del tallo, mostraron un efecto significativo de la interacción población por tratamiento, indicando niveles altos de plasticidad y variación de la plasticidad de las características medidas. Este alto número de interacciones significativas sugiere que las poblaciones de Capsicum annuum silvestre tienen el potencial para responder a ambientes variables en la disponibilidad de luz. Además se probó la respuesta adaptativa a la luz estimando la relación entre las características fenotípicas y el número de semillas por planta como una medida de la adecuación. En el tratamiento medio de luz, la selección favoreció un aumento en la longitud y ancho de la hoja y una disminución en el diámetro del tallo. En el tratamiento bajo de luz, la selección favoreció una disminución del diámetro del tallo. Estos resultados indican que la selección y la deriva génica pueden ser responsables de los patrones de variación en la plasticidad observados en las poblaciones de Capsicum annuum silvestre. Palabras clave: Capsicum annuum silvestre, diferenciación entre poblaciones, norma de reacción, plasticidad fenotípica, respuestas a la luz.Abstract: Phenotypic plasticity allows plants to cope with heterogeneous environments. Wild Capsicum annuum is a valuable resource genetic that inhabits sites differing in light availability. We evaluated the genetic variation among populations, the phenotypic plasticity and its variation in response to three levels of light (high, 100%; medium, 50%; y low, 25% of sun light) of five wild Capsicum annuum populations from northtwestern Mexico. The traits measured were: plant height, stem diameter, leaf length, leaf width, fruit number, number of seeds per fruit, number of seeds per plant, and seed weight. Populations differed significantly in all traits measured. All characters showed significant treatment effect and all traits, except stem diameter showed significant population by treatment interaction effect, indicating high level of plasticity and variation in plasticity in the traits measured. This high number of significant interactions suggests that the populations of wild Capsicum annuum have the evolutionary potential for respond ...

Sinaloa State is the main producer of tomatoes (Solanum lycopersicum L) in Mexico where production attained 15,784 ha in 2008 (3). Fusarium wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici (Sacc) Snyder & Hansen causes significant yield losses in Sinaloa each year (2). Three pathotypes or races of F. oxysporum f. sp. lycopersici have been described: races 1, 2, and 3 (1). The purpose of this study was to determine the races of F. oxysporum f. sp. lycopersici present in Sinaloa and distribution of these races in the region. F. oxysporum f. sp. lycopersici isolates were obtained from plants showing symptoms of yellowing and necrosis of vascular bundles. Plants were sampled from 50 fields throughout the production area in Sinaloa from November 2008 to March 2009. Four differential cultivars were used to identify the races of 26 F. oxysporum f. sp. lycopersici isolates collected across Sinaloa: Bonny Best (susceptible to all races), UC-82-L (susceptible to races 2 and 3), F1 MH-1 (susceptible to race 3), and IR-3 (resistant to all races). A microconidial suspension was prepared for each isolate (1 × 106 CFU/ml) from cultures grown in potato dextrose broth with constant agitation (110 rpm) at 28°C for 7 days. Five 25-day-old seedlings (three fully expanded true leaves) from each differential cultivar were immersed in the appropriate microconidial suspension for 10 min, then individually transplanted into a pot containing 1 kg of sterilized commercial potting mix, and grown in a growth chamber at 25 to 28°C and 60 to 75% relative humidity for 5weeks with 14-h light/10-h darkness. Control plants (root dipped for 10 min in sterile water) were grown similarly and remained asymptomatic. Susceptible cv. Bonny Best showed typical symptoms of Fusarium wilt including epinasty, yellowing, defoliation, vascular necrosis, and wilt. None of these plants survived 25 days postinoculation for any of the isolates. All UC-82-L plants inoculated with each of the 26 isolates died before 35 days, indicating that none of the isolates was of race 1. F1 MH-1 plants only survived inoculation with 3 of the 26 isolates (11.5%), indicating that the 23 isolates that killed these plants (88.5% of the 26 isolates) were of race 3, and only 3 isolates were of race 2. All IR-3 plants inoculated with the 26 isolates survived. The isolates showed variation in response to the differential cultivar UC-82L in duration from inoculation to when the plants died (variation in isolate aggressiveness). The three F. oxysporum f. sp. lycopersici race 2 isolates were restricted to the Culiacan Valley, whereas the 23 F. oxysporum f. sp. lycopersici race 3 isolates were widely distributed across Sinaloa. Koch's postulates were confirmed by reisolating the fungus from the roots and stem base of each dead, inoculated plant (4). This study provides baseline data for future surveys to monitor changes in distribution of F. oxysporum f. sp. lycopersici races in Sinaloa, Mexico. References: (1) G. Cai et al. Phytopathology 93:1014, 2003. (2) P. Sánchez-Peña. Programa de Fomento y Apoyo a Proyectos de Investigación (PROFAPI), Universidad Autónoma de Sinaloa, México, 2007. (3) Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación, Servicio de Información Agroalimentaria y Pesquera, México. www.siap.gob.mx , 2009. (4) B. A. Summerell et al. Plant Dis. 87:117, 2003.

<p><strong>Background: </strong><em>Pepper huastecto yellow vein virus</em> (PHYVV) is one of the main viruses affecting pepper (<em>Capsicum</em> spp.) plants in Mexico.</p><p><strong>Question: </strong>Why there are no pepper resistant cultivars to PHYVV currently? Could it be due for the lack of new pepper resistant sources and knowledge about the heritability of the resistant trait?</p><p><strong>Study species: </strong><em>Capsicum annuum, Pepper huasteco yellow vein virus </em>and<em> Bemisia tabaci</em>.</p><p><strong>Study site: </strong>Culiacan<strong> </strong>Sinaloa, Mexico; January 2013 to August 2014.</p><p><strong>Methods: </strong>Two assays were performed in 2013 and 2014 with three resistant wild lines of <em>Capsicum annuum</em> in the S2 and S3 generation under greenhouse conditions to analyze the resistance to the <em>Pepper huasteco yellow vein virus</em> (PHYVV) and its heritability. Plants were inoculated with PHYVV through <em>Bemisia tabaci</em> G. and by grafting.</p><p><strong>Results: </strong>Line UAS12 showed a significantly higher proportion of resistant plants, longer incubation time, and less amount of viral DNA, followed by lines UAS13, UAS10 and the Maverick cultivar under both inoculation methods in both assays. Distribution of symptoms revealed a bimodal tendency in both assays. The novel gene "<em>CchGLP</em>" which confer resistance to PHYVV in pepper plants, was identified in the three lines evaluated on this study. Heritability of line UAS12 was of 0.35 and 0.26 in the insects and grafting inoculations, and of 0.58 and 0.10 in the first and second assays, respectively. Lines UAS13 and UAS10 showed close to zero heritability in the first and second assays with both inoculation methods.</p><strong>Conclusions: </strong>Line UAS12 is the most promising genetic resource for its high resistance and for showing heritability for the resistance trait. The intermediate resistance of lines UAS13 and UAS10 could be also useful for breeding programs. At least two genes are involved in the resistance trait to PHYVV. Part of the resistance shown in these lines may be due to the presence of the "<em>CchGLP</em>" gene. Line UAS12 count with variability for the resistant trait and can, therefore, be used to improve resistance and the other two lines possibly are stable as they did not show heritability.

Intensive tomato (Solanum lycopersicum L.) production in coastal areas of Sinaloa is exposed to significant amounts of Cl and Na deposited by sea breezes and irrigation water, which affects the yield of this vegetable. The aim of this study was to evaluate three percentage ratios of Cl-/anions (25/100, 50/100 and 75/100) and three percentage ratios of Na+/cations (25/100, 50/100 and 75/100) in the nutrient solution on mineral composition, dry matter production and yield of tomato. The experimental design was completely randomized with a 32 factorial arrangement and four replications. Analysis of variance and mean comparisons were performed (Tukey, P ≤ 0.05). Cl and Na concentrations in tomato leaves, stems and fruits increased significantly with increasing ratios of Cl-/anions and Na+/cations in the nutrient solution. The 75/100 Cl-/anions ratio reduced (P ≤ 0.05) the Ca concentration in leaves, while the 75/100 Na+/cations ratio decreased (P ≤ 0.05) K concentrations in leaves and stems. Both ratios reduced aerial dry biomass (48 and 25.8 %, respectively) and tomato yield (50.8 and 45.7 %, respectively). The results indicate that tomato plants grown with the 75/100 percentage ratio of Cl-/anions or the 75/100 percentage ratio of Na+/ cations absorb excessive amounts of Cl or Na, which causes ionic imbalance (especially of K+ and Ca2+) and affects dry matter production and yield.

El níquel (Ni) es un micronutrimento para plantas superiores; la información sobre este elemento y sus efectos en el rendimiento de los cultivos agrícolas es escasa, lo cual contribuye a que los productores hortícolas de México no lo apliquen en sus sistemas de producción. El rendimiento de pimiento morrón (Capsicum annuum cv. Cannon) cultivado en casa sombra y riego por goteo se afecta por la aplicación de Ni2+ al alterar las concentraciones nutrimentales en los órganos vegetales. El objetivo de este estudio fue evaluar cuatro concentraciones de Ni2+ en solución nutritiva (SN) (0, 0.5, 1.0 y 1.5 mg L-1) en la composición mineral y el rendimiento de pimiento morrón. El diseño experimental fue bloques completos al azar y cuatro repeticiones. Las variables evaluadas fueron la composición mineral de hojas, tallos y frutos, y peso, diámetro, longitud, número y el rendimiento de frutos (PF, DF, LF, NF y RF). Los resultados se analizaron con ANDEVA y los promedios se compararon con la prueba de Tukey (p£0.05). El Ni2+ disminuyó las concentraciones de Cu y Zn en hojas e incrementó las concentraciones foliares de Ni, Fe, Mg, y la de N en frutos. Aunque no hubo diferencias significativas en el rendimiento, la producción mayor (71.32 Mg ha-1) se obtuvo con 1.0 mg Ni2+ L-1 en la SN, superior en 10.63 Mg ha-1 a la del tratamiento sin Ni2+ (60.69 Mg ha-1). El níquel no se detectó en los frutos, los cuales pueden consumirse en fresco sin riesgos para la salud humana. La aplicación de 1.0 mg Ni2+ L-1 en la SN aumentó en 14.9% el rendimiento de pimiento morrón cultivado en casa sombra y riego por goteo.