The establishment of clonal seed orchards is a viable option for the continuous production of improved seed of desired genotypes. Grafting is the main technique used to establish clonal seed orchards. The objective of this study was to examine how the geographic location and the age class of the donor trees of buds, the phenological status of the buds, and the anatomical characteristics of the scions and the rootstocks affect the survival and growth of Pinus engelmannii Carr. grafts. Scions were collected from two trees in each of three age classes (young, middle-aged, and old). Grafting was performed with buds in two physiological states (end of dormancy and beginning of sprouting). Cross-sections of the grafted organs were obtained for anatomical analysis. A Cox proportional hazards model was used to determine the effects of the variables that were considered. The age class of the scion donor trees, the total area of the cut surface of the scion, and the density of resin channels in the scions significantly affected (p < 0.05) survival of the grafts. By contrast, the physiological state of the buds and the other anatomical characteristics of the grafted organs did not significantly affect graft survival. In P. engelmannii, grafting was most effective when scions from middle-aged trees were used. Graft survival was enhanced by a small total area of the cut surface of the scion and low density of resin channels in the scions. The area of the cambium of the scions directly influenced growth of the grafts.

Rooting substrate and fertilization are key components in the production of containerized seedlings, as they can influence the morphological and physiological characteristics of the plants, which in turn can impact outplanting performance. The objective of the study was to evaluate the effect of four substrates based on mixtures of peat moss (PM), composted bark (CB) and raw pine sawdust (PS), combined with two doses of controlled release fertilizer (CRF) and one non-fertilized control, on the growth of Pinus cembroides Zucc. in the nursery. The treatments were: M1: 50+25+25, M2: 25+25+50, M3: 25+50+25 and M4: 50+50+0 of PM+ CB+ PS (% by volume), respectively. Fertilizer treatments used a controlled release fertilizer (Multicote^®): F1: 3 kg m⁻³ and F2: 6 kg m⁻³ and a control (WF: with no added fertilizer). The treatments were distributed in a randomized complete block design, with a factorial arrangement of 4 × 3 and six replications. The variables evaluated were: height, seedling diameter, dry biomass, Dickson Quality Index, N, P and K content. Regardless of the substrate, the high fertilizer dose (6 kg m⁻³) improved most morphological variables. In addition, the high fertilizer dose resulted in foliar N, P and K concentrations within recommended ranges for all substrates. The substrate containing only peat moss and composted bark (M4 + F1 and M4 + F2) had the best growth response. However, the substrate composed of 25% peat moss, 50% composted bark and 25% raw pine sawdust with the high fertilizer dose (M3 + F2) resulted in acceptable seedling growth, and may be preferred if the cost of the substrate is a concern to nursery manager.

Substrate is a factor that significantly influences the quality and production costs of nursery seedlings. The objective of this study was to evaluate combinations of peat moss, composted pine bark, and fresh pine sawdust in order to identify the proportions that favour the quality of Pinus engelmannii Carr. seedlings and minimise the production costs in the nursery. Substrates were formed using mixtures of peat moss (15% to 50%), composted pine bark (15% to 50%) and fresh pine sawdust (20% to 70%), with 2, 4 and 6 g L⁻¹ of controlled release fertilizer (Multicote^®, Haifa, Israel). A completely randomised experimental design with a factorial arrangement of 7 × 3 was used. The evaluated factors are root collar diameter, biomass, N-P-K content, and production costs of the substrates which were determined based on the container volume and three commercial quotations. Significant differences were found in root collar diameter and biomass, highlighting the treatments using 50% to 70% sawdust with 6 g L⁻¹ of fertilizer. Assimilated values of N-P-K were acceptable in all treatments with 4 and 6 g L⁻¹ of fertilizer. In the substrates with high percentages of sawdust, seedlings with morphological characteristics and nutritional levels within the values recommended for conifers were produced. In addition, it was possible to reduce the production cost of the substrates by up to 67%.

Se estudió el efecto de citocininas y auxinas en la producciónde brotes adventicios de Agave durangensis in vitro. La germinación sehizo en medio de cultivo Murashige y Skoog (MS) al 50% de concentración,sin reguladores de crecimiento. La producción y desarrollo de brotesadventicios se realizó en medio de cultivo MS al 100%, con citocininas (KINy BAP) y ANA como auxina, evaluando diferentes concentraciones en 12tratamientos. La concentración de 4.0 mg L-1 de BAP sin auxinas presentómejores resultados en altura del explante, número de hojas por explante,número de brotes por explante y número de hojas por brote. La presenciade auxinas sólo favoreció la altura del brote en el tratamiento de 4.0 mg L-1KIN y 0.4 mg L-1 ANA. Por lo anterior, resulta viable utilizar solo citocininasen medio de cultivo en la etapa de producción de brotes de A. durangensis.

One of the most important effluents in Guadiana Valley, Durango is El Tunal River, mostly used for agricultural and livestock supply. This river has been polluted by agricultural activity and wastewater discharges. Thus, this study aimed to evaluate the current quality of water and agricultural soil near the river, to estimate the environmental situation of the agricultural sector and its main pollution sources. Hence, a total of 24 soil and five water samples were taken, analysing parameters of organic matter, pH, nutrients, and heavy metals(loid)s (As, Cd, Pb, Zn) in five agricultural areas. The randomised experimental design showed significant variations in soil ( p < 0.05) of organic matter, nitrogen, As, and Pb between sampling points, confirming suitable conditions for agriculture. Although contamination by heavy metal(loid)s exists, it is below permitted levels. In contrast, the physicochemical quality of the water indicated high levels of phosphates, total dissolved solids, and total coliforms, mainly in the nearest site of a wastewater treatment plant, thus the quality of the water is not suitable for consumption and irrigation for sensitive crops. Nevertheless, rainfall contributes to improve the quality of the river by diluting pollutants. Moreover, constant use of this water might represent a risk to human health and agriculture as it could transport elements to crops or soil, becoming a severe environmental problem.

La información sobre la distribución de las plagas forestales en función a su preferencia climática en la región de la Sierra Madre Occidental del estado de Durango es escasa. El presente estudio analizó la distribución de las especies Dendroctonus frontalis/mexicanus, D. valens, Ips pini, Ips lecontei y otros insectos, utilizando la herramienta MaxEnt (Máxima Entropía). Los registros obtenidos sobre la presencia de estos insectos fueron proporcionados por la Secretaria de Recursos Naturales y Medio Ambiente (SRNyMA) del estado de Durango. Los modelos resultantes son razonables de acuerdo al valor del estadístico Área Bajo la Curva (AUC) utilizado para su validación. Con un aproximado de 118 mil hectáreas (idoneidad alta) Dendroctonus frontalis/mexicanus fue la especie que destacó en esta variable. Por otra parte, las variables más importantes para el modelamiento de las especies analizadas son las derivadas de la temperatura.