The aim of this research work was to identify the Boundary-Line Approach (B-LA) macro-nutrient optimum concentrations linked to maximum yield and sufficiency ranges at 90% maximum yield per 1-year-old fructification cladode for Opuntia ficus-indica (L.) Miller variety "Rojo Pelón". Four years' (2012-2015) data of yield per fructification cladode and macro-nutrient concentration [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), or magnesium (Mg)] were used to elaborate bivariate scatter diagrams (n = 228). Selection from 9 to 11 points was performed to estimate quadratic functions as boundary-lines in each bivariate scatter diagram. The vertices allowed estimation of the optimum macro-nutrient concentrations:

The aim of the current study was to determine the monthly total soluble sugar concentration in the stem and root of the Wichita and Western walnut (Carya illinoinensis) varieties during a productive cycle in northern Mexico. Vegetable samples were obtained using a systematic sampling method, and processed by means of a spectrophotometric assay to determine the total soluble sugars (TSS) concentration in productive walnut trees. Data analysis was performed by means of a 2-way ANOVA. The results of the TSS concentration had differences throughout the months of an annual productive cycle, and were also different between the evaluated walnut varieties. The highest total soluble sugar concentration in stem and root were in the lowest temperature months, and it decreases in both tissues when the environmental temperature rises. The Wichita variety had a higher total soluble sugar concentration than the Western in every month during the productive cycle. Further research is required to assess the effect of other type of factors including environmental or agronomic over the dynamics of the total soluble sugars in productive walnut trees.

El trabajo se realizó en dos etapas, en la primera se formaron las cruzas en el campo experimental de la Universidad Autónoma Agraria Antonio Narro Unidad Laguna (UAAAN-UL), y en la segunda la evaluación en el campo experimental de la UAAAN-UL en los ciclos agrícola primavera y verano, y en el ejido Niágara, en el municipio de Aguascalientes, Aguascalientes, en primavera. El material genético fueron 17 líneas endogámicas, cuatro de la UAAAN-UL, dos del INIFAP y 11 del CIMMYT. El objetivo fue estimar la aptitud combinatoria general (ACG) de las líneas, la aptitud combinatoria especí ca (ACE) y cuanti car los efectos genéticos y la heterosis de las cruzas. Para la ACG sobresalieron las líneas macho LAN-388P, LB-32 y LB-40, y las líneas hembras CML-319, CML-318 y CML-278; para la ACE los mayores valores lo tuvieron las cruzas LAN-123xCML-278 (3.28 t ha−1), LAN-123xCML-318 (1.9 t ha−1), LB-40xCML-319 (1.7 t ha−1) y LAN-388PxCML-264 (1.52 t ha−1). Mientras que el mayor rendimiento de grano, lo tuvieron las cruzas LB-40xCML-319 (14.49 t ha−1), LB-32xCML-319 (14.17 t ha−1), LAN-388PxCML-264 (13.68 t ha−1), LAN-123xCML-278 (13.55 t ha−1) y LAN-388PxCML-278 (13.44 t ha−1). La varianza de dominancia superó a la varianza aditiva en rendimiento de grano (RG) y en los principales componentes del rendimiento. Se encontraron efectos positivos de heterosis para rendimiento de grano con respecto al progenitor superior en las cruzas LB-40xCML-319 y LB-32 x CML-319.

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