Estimação de parâmetros genéticos e análise de trilha em uma população de milho com potencial para seleção recorrente
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2018-10-19
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Universidade Federal de Goiás
Resumo
Recurrent selection in half-sib progenies is the most used method for breeding maize
populations. To be efficient, this method needs to count on populations that have genetic
variability potential to be explored for agronomic traits of interest. In this sense, genetic and
phenotypic parameters are estimated at each cycle in order to verify the magnitude and
maintenance of the present variability, the possible gains with the selection and, thus, the
potential and permanence of the population in the recurrent selection program. These
parameters guide the best selection strategies to be adopted for the management of the
breeding program. The objective of this study was: (i) to evaluate the genetic potential of the
“Composto Calor” maize population (CCR1) for grain yield and its components to recurrent
selection; (ii) compare the genetic gains obtained by the direct selection in grain yield with
those obtained by the Z Index and the Mulamba & Mock Index; and (iii) to estimate genetic
and phenotypic correlations between agronomic traits and the cause and effect relationships
of the yield components with grain yield to establish criteria in the indirect selection process.
Thus, 141 half-siblings progenies and three checks were evaluated using a 12 x 12 triple
lattice design in 2017/2018 growing season in the UFG, Goiânia-GO and second crop
2017/2018 in the UFJ, Jataí-GO. The traits evaluated were: number of days to anthesis,
number of days to silking, anthesis-silking interval, plant height, ear height, ear ratio, stalk
lodging, ear prolificacy, kernels per row, number of grains per row, ear diameter, ear length,
cob diameter, grains length, ear weight and grain yield. Significant differences were found
among progenies for all traits, indicating the presence of variability. The genetic gains with
selection ranged from -38.19% for anthesis-silking interval to 10.86% for grain yield, and the
selection index of Mulamba & Mock showed better indirect response for this last trait. All traits
exhibited at least one significant genetic or phenotypic correlation estimate, indicating that
changes in one trait may change the mean of other correlated. Therefore, the CCR1
population has potential to recurrent selection, the selection index of Mulamba & Mock is more
efficient in the selection of the progenies to be recombined in successive selection cycles, and
plant height, ear diameter, and ear weight are the most appropriate traits to perform
selection aiming to achieve indirect genetic gains for grain yield.
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Citação
CRISPIM FILHO, A. J. Estimação de parâmetros genéticos e análise de trilha em uma população de milho com potencial para seleção recorrente. 2018. 95 f. Dissertação (Mestrado em Genética e Melhoramento de Plantas) - Universidade Federal de Goiás, Goiânia, 2018.