EFFECT OF IRRIGATION SUSPENSION IN PRE-FLOWERING AND GRAIN FILLING IN THE CONTENTS OF LYSINE, TRYPTOPHAN AND YIELD IN TWO HIGH PROTEIN QUALITY MAIZE

In order to understand the influence of the suspension of irrigation in pre-flowering and grain filling, in the content of lysine and tryptophan of two high quality protein maize hybrids (H-559C and CML176xCML177) and a normal maize (H-516), an experiment was established during the autumn/winter 2005 season at the experimental station "La Nortena" in the region of Soconusco, Chiapas, Mexico. Irrigation, suspension of irrigation in pre-flowering and suspension on grain filling in three maize materials were tried. In total, there were nine treatments with three replications each. They were established under an arrangement of plots divided and distributed in a complete random design at in the field. Morphological and physiological variables performance by sampling and treatment were assessed. Results were statistically analyzed and compared with the Tukey test (P <= 0.01). Results showed that the suspension of the irrigation produced alterations in water relations in the two phenological stages, differently in each genotype. The suspension of irrigation in pre-flowering induced reductions of lysine and tryptophan contents in H-559C, while lysine content declined in CLM176xCLM177 when the suspension of irrigation was applied during grain filling. The suspension of irrigation in the pre-flowering stage impacted the yield of all the evaluated materials and affected more their morphology, physiology and yield of high quality protein, in comparison with the suspension of irrigation in the maize grain filling stage.