Induced systemic resistance (ISR) is a mechanism involved in the plant defense response against pathogens. Certain members of the Bacillus genus are able to promote the ISR by maintaining a healthy photosynthetic apparatus, which prepares the plant for future stress situations. The goal of the present study was to analyze the effect of the inoculation of Bacillus on the expression of genes involved in plant responses to pathogens, as a part of the ISR, during the interaction of Capsicum chinense infected with PepGMV. The effects of the inoculation of the Bacillus strains in pepper plants infected with PepGMV were evaluated by observing the accumulation of viral DNA and the visible symptoms of pepper plants during a time-course experiment in greenhouse and in in vitro experiments. The relative expression of the defense genes CcNPR1, CcPR10, and CcCOI1 were also evaluated. The results showed that the plants inoculated with Bacillus subtilis K47, Bacillus cereus K46, and Bacillus sp. M9 had a reduction in the PepGMV viral titer, and the symptoms in these plants were less severe compared to the plants infected with PepGMV and non-inoculated with Bacillus. Additionally, an increase in the transcript levels of CcNPR1, CcPR10, and CcCOI1 was observed in plants inoculated with Bacillus strains. Our results suggest that the inoculation of Bacillus strains interferes with the viral replication, through the increase in the transcription of pathogenesis-related genes, which is reflected in a lowered plant symptomatology and an improved yield in the greenhouse, regardless of PepGMV infection status.

Sustainable crop production systems can be attained by using inputs efficiently and nitrogen use efficiency (NUE) parameters are indirect measurements of sustainability of production systems. The objective of this study was to investigate the effect of selected nitrogen (N) management treatments on wheat yields, grain and straw N concentration, and NUE parameters, under conservation agriculture (CA). The present study was conducted at the International Maize and Wheat Improvement Center (CIMMYT), in northwest, Mexico. Seventeen treatments were tested which included urea sources, timing, and methods of fertilizer application. Orthogonal contrasts were used to compare groups of treatments and correlation and regression analyses were used to look at the relationships between wheat yields and NUE parameters. Contrasts run to compare wheat yields or agronomic efficiency of N (AE_N) performed similarly. Sources of urea or timing of fertilizer application had a significant effect on yields or AE_N (p > 0.050). However, methods of application resulted in a highly significant (p < 0.0001) difference on wheat yields and agronomic efficiency of N. NUE parameters recorded in this study were average but the productivity associated to NUE levels was high. Results in this study indicate that wheat grew under non-critically limiting N supply levels, suggesting that N mineralization and reduced N losses from the soil under CA contributed to this favorable nutritional condition, thus minimizing the importance of N management practices under stable, mature CA systems.

Grafting cucurbitaceous crops is an alternative for protection of plants in production systems with biotic or abiotic stress. The grafting cucumber improves the plant growth and development under adverse conditions, such as drought, high salt concentration and soil-borne pathogens. Lagenaria siceraria is a species with potential rootstocks in cucumber. Mexican L. siceraria accessions are less susceptible to damage caused by Meloidogyne incognita. The aim of this study was to evaluate two Mexican L. siceraria accessions (Lag 48 and Lag 53) and Forticuke F1(Numhems®) as rootstocks on plant growth and fruit quality of cucumber in soil infested with root-knot nematodes.Plant ungrafted was used as control. The results show that rootstocks increased plant height, leaves number and leaf area. Forticuke F1 and Lag 53 had a greater response than ungrafted plant. Thegrafting increased fruit weight in 25.3%, 15.2% and 14.6% with Forticuke F1, Lag 53 and Lag 48,respectively. Internal firmness of the fruits increased by 56.4% in Forticuke F1, 12.6% in Lag 53 and 2.2% in Lag 48 with respect to ungrafted plants. Length, diameter, external firmness and Brix degrees of fruit were not modified by rootstock effect. The use of L. siceraria as rootstock is an alternative to improvement plant growth and fruit quality of cucumber in soil infested with root-knot nematodes.

Intrinsic soil fertility and the method of irrigation can affect the efficiency of nitrogen (N) fertilization, modify the yield goal, growth, and nutritional status of crops. A study was carried out with the objective of determining yield, growth, water use efficiency (WUE), agronomic efficiency of N (AEN), NO3- concentration in petiole cell extract (PCE) and chlorophyll index (SPAD) in a cotton crop by effect of N rates and two irrigation methods. The study consisted of two experiments established in soils of high fertility [˃13 g kg-1 organic matter (OM) and N-NO3- ˃ 30 mg kg], with varying N fertilization rates: a) flood irrigation (FRR, 11 and 220 kg N ha‑1), and b) drip irrigation (FRG, 11 to 440 kg N ha-1). Plant height and number of nodes were not affected by the applied treatments. SPAD values and NO3- concentrations in PCE were cubically related to crop yield. The highest yield and WUE was obtained in the experiment with drip irrigation. In the FRR experiment no response (P > 0.05) to N fertilization treatments was found. In the FRG experiment, application of 440 kg N ha‑1 reduced yield by 43% compared to the rest of the evaluated rates. AEN was statistically higher (P < 0.001) in treatments fertilized with 11 kg N ha‑1. The low yield response due to application of N in cotton was attributed to high concentrations of N-NO3- and OM that are present in the soils in which the experiments were conducted.

Due to health benef its, organic food products have increased their demand in recent years. The objective was evaluating the effects of three ecological nutrient solutions, (Tea of compost, vermicompost, and leachate of vermicompost), on yield and quality of melon plants. As a control, an inorganic nutrient solution was used. Our results showed that compost tea promoted fruit yield equivalent to the inorganic nutrient solution. Plants fertilized with compost tea yielded fruits with the highest value of soluble solids content (9.98 ºBrix). Regarding antioxidant capacity, fruits fed with compost tea and vermicompost leachate obtained higher values than fruits fed with nutrient solution, fruits fed with vermicompost leachate obtained statistically higher values than fruits fed with chemical nutrient solution. Concerning to total phenolic content plants fed with vermicompost leachate obtained the highest value statistically similar to control plants fed with the Steiner nutrient solution.

En escenarios de escasez de agua, el manejo del riego en cultivos es de gran importancia. El objetivo de este trabajo fue identificar la tensión de humedad (T) óptima en suelo para producir el mayor crecimiento y rendimiento de maíz (Zea mays L.) cultivado en el valle de Mexicali, Baja California, México. El cultivo fue establecido durante el ciclo primavera-verano de 2017. Los tratamientos evaluados fueron cuatro tensiones de humedad [(T); (10, 20, 30 y 40 kPa)] y seis genotipos de maíz (G). Los tratamientos se distribuyeron bajo un diseño de bloques al azar con cuatro repeticiones (arreglo factorial doble). El primer factor fue tensión de humedad del suelo y el segundo factor la variedad de maíz. Se midió el crecimiento del cultivo expresado como altura, número de hojas, días a floración masculina (antesis), y área foliar. Al final del experimento se cosecharon las mazorcas de cada tratamiento y se calculó el peso de grano, rendimiento y eficiencia en el uso del agua de riego. No se encontró una interacción significativa entre las variables de respuesta evaluadas (T × G) (P > 0.05). Durante los primeros 50 días después de la siembra, el factor que más afectó al crecimiento y desarrollo fue T. Con una menor T, menor fue el número de días para alcanzar la etapa de floración masculina (P < 0.05). El rendimiento y la eficiencia en el uso del agua de riego fueron afectados por T y G (P < 0.05). La variedad Asgrow RX 717 presentó la floración masculina en un menor tiempo que el resto de los genotipos, el más alto rendimiento (10.63 Mg ha-1) y la mayor eficiencia en el uso del agua de riego (48.79 kg ha-1 mm-1) que el resto de los genotipos evaluadas (P < 0.05).