Estimação de parâmetros genéticos em populações de seleção recorrente em milho
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2018-08-02
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Universidade Federal de Goiás
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Among the several maize breeding methods (Zea mayz L.), recurrent selection using half-sib families is an efficient and easy-to-conduct strategy. The efficiency of this method depends, among other factors, on the estimation of genetic and phenotypic parameters during the selection cycles to guide the strategies of the breeding program and for selection to occur in the desired direction for the various traits of interest. The objective of this research was to estimate genetic and phenotypic parameters of two maize populations during the third cycle of recurrent selection, to evaluate its potential for future selection cycles and to verify the efficiency of indices for the simultaneous selection of multiple traits. 160 families of half-siblings of the populations CRE-01 and CRE-02 were evaluated in the experimental area of the School of Agronomy of UFG in the 2017/2018 growing season using a randomized block design with three replicates. The families were evaluated for male flowering (MF), female flowering (FF), flowering interval (FI), plant height (PH), ear height (EH), relative ear position (REP), ear length (EL), number of grain rows (NR), number of grains per row (NGR), lodging and breaking (LB), prolificacy (PROL), grain length (GL), ear diameter (ED),ears weight (EW), weight of four ears (W4E), weight of grains of four ears (WG4E), grain yield (GY), and weight of one hundred grain (W100). The selection gain for each traits and the gain with the indirect selection were estimated using the Smith and Hazel (ISH), Mulamba and Mock (IMM) and Z (IZ) indices. Significant differences were observed between families in both populations for all traits, except for GL and LB in CRE-02 population, indicating that populations have potential for continuity of the recurrent selection program. Inheritability estimates ranged from 6.54% for REP to 96.92% for EW. The selection gain varied from 1.66% (NR) to 45.56% (GY) in the CRE-01 population, and from 1.00% (GL) to 81.37% (EW) in the CRE-02 population. Genetic correlations were observed between GY and 11 (CRE-01) and 12 (CRE-02) of the 18 other traits evaluated, in the favorable sense for all the traits, except for PH and EH. There was a greater coincidence of families selected between ISH and IZ indexes (above 65%). In general, the IZ provided better gains for the traits of interest and it is recommended for multiple trait selection during recurrent maize selection program.
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SILVA, E. M. Estimação de parâmetros genéticos em populações de seleção recorrente em milho. 2018. 71 f. Dissertação (Mestrado em Genética e Melhoramento de Plantas) - Universidade Federal de Goiás, Goiânia, 2018.