Respuesta fisiológica de cultivares de arroz a diferentes épocas de siembra en en Córdoba, Colombia.

A greater efficiency of rice cultivation is based on knowing its characteristics in terms of growth and yield according to the environmental supply. This research aimed at determining the dry mass (DM) g, leaf area (LA) cm2, absolute growth rate (AGR) g day-1, relative growth rate (RGR) g g-1 day-1, net assimilation rate (NAR) g cm-2 dia-1, leaf area ratio (LAR) cm-2 day-1 and leaf area index (LAI) and yield components of plant height, panicles per m2, grains per panicle, weight of 1000 grains and yield t ha-1, of Fedearroz 2000, Fedearroz 50, Fedearroz Mocarí and Fedearroz 473 cultivars under irrigation, during the sowing season ranging from october to december, with a randomized block design with factorial arrangement 4x3 and four replications, while doing sampling for 15 days. The results showed high differences between sowing times, where the highest values of DM were presented in october, the LAI in November, RGR, RGR, NAR and LAR in october and november, where the cultivars showed more stability to environmental factors. The variables plant height, panicles per m2, numbers of grains per panicle and weight of 1000 grains did not present significant difference in one month to another; However the cultivars fedearroz 2000 and fedearroz 50 reached the maximum values in november, the yield presented highly significant differences in the seasons of november and december for the Fedearroz 2000 and Fedearroz 473 cultivars. To conclude, the greater physiological efficiency of the cultivars is presented in the sowing seasons of november and december. [ABSTRACT FROM AUTHOR]