RESUMEN. El objetivo del estudio fue determinar el efecto del biofertilizante y del nitrógeno en la variedad sintética de maíz VS-535 sobre la ocurrencia de las fases fenológicas, análisis de crecimiento, rendimiento, componentes, eciencia en el uso del agua, contenido de nitrógeno y la rentabilidad. La siembra se realizó el 10 de julio de 2012, los tratamientos fueron la inoculación de biofertilizante y la aplicación de 0, 80 y 160 kg hade nitrógeno. Se contabilizó el número de hojas y el área foliar, con lo que se calculó el índice (IAF) y la duración de área foliar (DAFT). También se determinó el contenido de materia seca (MS), las tasa de crecimiento del cultivo (T CC), y la tasa de asimilación neta (T AN ). En madurez siológica se evaluó el contenido de materia seca (MS) y el rendimiento de grano (RG), se calculó la eciencia en el uso del agua y del nitrógeno, y se realizó un análisis económico. Con 160 kg ha . Para RG la mayor respuesta se encontró con biofertilizante y nitrógeno a 160 kg ha −1 , lo que genero la mayor rentabilidad del cultivo.Palabras clave: Área foliar, fenología, grano, nutrición, variedad sintética ABSTRACT. The objective of the study was to determine the eect of biofertilizer and nitrogen on the synthetic variety of VS-535 corn, on the occurrence of phenological phases, growth analysis, performance, components, water use eciency, nitrogen content and protability. The sowing was performed on July 10, 2012, the treatments were the inoculation of biofertilizer and the application of 0, 80, and 160 kg ha −1 of nitrogen. The number of leaves and leaf area were counted, calculating the index (LAI) and leaf area duration (TLAD). The dry matter (DM) content was also determined, as well as the crop growth rate (CGR) and the net assimilation rate (NAR) was also evaluated. On physiological maturity, the dry matter (DM) content (DM) and grain performance (GP) were evaluated; the eciency in the use of water and nitrogen was calculated, and an economic analysis was performed. It had the highest LAI and TLAD with 160 kg ha −1 of nitrogen.For DM, EUA, EAN, CGR, while the older N AR were with biofertilizer and nitrogen at 80 and 160 kg ha .For GP, the highest response was found with biofertilizer and nitrogen at 160 kg ha-1, which generated the highest protability of the crop.

Wheat (Triticum aestivum L.) yields often are closely related to spike number per unit ground area. This study was conducted to determine whether, for soft white winter wheat in a region with a humid continental climate, this relationship is determined primarily by changes in total dry weight accumulation (TDW), harvest index (HI), or both. The study involved several field experiments in which seeding density varied from 6 to 24 g m−2, sowing dates ranged from 14 September to 1 November, alternate rows were removed in May and early June, row spacing varied from 0.16 to 0.32 m, a growth regulator (chloroethyltrimethylammonium chloride) was applied 9.6 kg a.i. ha−1, and 11 genotypes (both gibberellic acid sensitive and insensitive) were used. These treatments were used to create range of final spike numbers. Grain yields ranged from 180 to 570 g m−2, and increased with spike numbers per m2. Total dry weight, which ranged from 720 to 1670 g m−2, also increased with spike numbers per m2, such that HI remained unchanged as spike number per unit area increased. Harvest index, however, decreased with spike number per plant, and was related to kernel weight but not to kernel number per spike. Positive relationships of grain yield to spike number per unit land area thus seem to arise from increased TDW rather than enhanced HI. Examination of the reasons for high dry matter production at high spike numbers appears worthwhile for subsequent research.