IMPACTO DEL ESTRÉS NITROGENADO SOBRE LA VARIABILIDAD POBLACIONAL DEL CRECIMIENTO, PARTICIÓN DE BIOMASA Y DESARROLLO REPRODUCTIVO.

ROSSINI, MARÍA DE LOS ANGELES; MADDONNI, GUSTAVO A.; OTEGUI, MARÍA E.

Rosario, Santa Fe

Congreso; IX Congreso Nacional de Maíz; 2010

AIAMBA y AGROACTIVA

Many papers describe the effects of radiation and nitrogen availability on maize grain yield per unit land area. However, little information exists about the variability among plants of the underlying process of kernel set under mentioned abiotic stresses. The objectives of this study were to analyze the effects of the interaction between plant population density and nitrogen availability on the temporal dynamics of population variability in plant growth, reproductive development, biomass partitioning to reproductive organs and kernel set. Field experiments were conducted with different combinations of planting density x nitrogen availability with two hybrids with different tolerance to crowding. Plant biomass variability decreased over time, and this effect was more pronounced under N fertilization treatments. This response highlights the impact of N supply to mitigate the initial biomass variability among plants of a stand, which can affect maize grain yield per unit land area. Under the most stressful conditions (i.e. high stand density x low N availability), the lower growth rate of plants was associated with a low rate of floral development, a reduced biomass partitioning to the ear around silking and a delayed dynamic of female flowering (i.e. more asynchronous silks emergence). The higher kernel set variability among plants detected at lower ear growth rates, was explained by the different reproductive development of female flowers and the higher kernel abortion of late emerged silks.