The objective of this work was to determine the developmental pattern of tillers in wheat genotypes showing contrasting number of tillers. The genotypes were tested under different seeding densities, in order to evaluate their effect on grain yield components. The experiment was performed in Capão do Leão County, Rio Grande do Sul State, Brazil, in 2006. Ten wheat cultivars, selected by their tillering ability, were tested in a split plot design, where plots were formed by the genotype (cultivar), and subplots by different seeding densities: 50, 200, 350, 500 and 650 seeds per square meter. Results indicated that tiller senescence is directly correlated to tillering potential of the genotypes, and genotypes with higher tillering ability presented higher senescence values, when subjected to higher seeding densities. The best adjustment of yield components is obtained from the adequate seeding density, which can be achieved by matching the density and tillering potential. Also, higher yield in genotypes with reduced tillering potential is achieved by increasing grain mass per ear, to compensate for their lower number of ears per area unit.
Triticum aestivum; developing stages; tillering potential; senescence; tiller survival
