This study aimed to evaluate the participation of the main stem and tillers of cv. IAC 102 rice in grain productivity, under flood irrigation, as a function of seeding density. The experiment was conducted under a plastic tunnel at FCA/UNESP-Botucatu, São Paulo State, Brazil, in 500-L capacity asbestos cement-water tanks containing a 30 cm layer of a Typic Udifluvent soil. The experimental design was a completely randomized setup, with four replicates. Seeding densities were 100, 200, 300, 400, 500, and 600 viable seeds per m², in four 1m-long rows per tank, spaced at 20 cm. Tillering decreased as seeding density increased, with greater participation of the main stems; however, this did not result in increased yield, due to the plasticity shown by rice plants, which yield components to adjust accordingly.
Oryza sativa; yield components; flood-irrigated rice; physiology of production
