Resumo

GARCIA, Pedro; SAN VICENTE, Félix; BEJARANO, Arnoldo  e  QUIJADA, Pablo. Inbreeding depression in tropical maize populations prior and following full-sib recurrent selection. Bioagro [online]. 2004, vol.16, n.1, pp.17-26. ISSN 1316-3361.

Full-sib recurrent selection (FSRS) was conducted in the following six tropical maize populations: (Suwan-1, Foremaiz-2, La Maquina, Compuesto Thai-1, Tuxpeño RC and Agua Blanca). The original populations (Co), their improved cycles (Cn), and S1 generation of both original and improved populations were evaluated in five locations in Venezuela. The objective of the study was to estimate inbreeding depression of the populations, before and after FSRS. Grain yield (GY), plant height (PH), ear height (EH), and days to silk (DS) were the traits used to estimate inbreeding depression. Inbreeding resulted in a significant reduction in GY, PH and EH and a significant increase in DS. For GY and PH inbreeding depression was significantly higher for the improved than for the original populations, whereas for EH and DS inbreeding depression rate and percentage were similar in both populations. Results suggest that for GY and PH dominance effects were more favored than for EH and DS. In general, Foremaíz-2 and La Máquina showed the highest inbreeding depression, while Agua Blanca showed the lowest. This suggests a greater accumulation of favorable alleles with selection than in Agua Blanca population.

Palavras-chave : Tropical corn; Zea mays; plant breeding.