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GENETIC VARIANCE COMPONENTS IN POPULATIONS DERIVED FROM SINGLE CROSS MAIZE HYBRIDS

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Author(s): FRANCISLEI VITTI RAPOSO | MAGNO ANTÔNIO PATTO RAMALHO

Journal: Revista Brasileira de Milho e Sorgo
ISSN 1676-689X

Volume: 3;
Issue: 3;
Start page: 402;
Date: 2004;
Original page

Keywords: Quantitative genetics | Reciprocal recurrent selection | Zea mays: Estimated response

ABSTRACT
This study was carried out to estimate the components of the intra and inter population genetic variance of two S0 maize populations derived from the AG9012 and C333 single cross commercial hybrids to assess their potential in intra and inter population recurrent selection programs. For this purpose, 169 random S0 plants were self-pollinated to obtain the S1 progenies. Seeds of each S1 progeny were used to generate intra and inter population half sib progenies and the remnant seed was stored. Therefore, S1 progenies and intra and inter population half sib progenies from each population were available. These three different progeny types from both populations were assessed at Ijaci-MG in the 2000/01 growing season, in a 13 x 13 simple lattice design with plots formed by a three-meter row. In all experiments, data on de-hulled corn ear weight were obtained and the genetic variance components estimated from the expected mean squares of the analyses of variance. The obtained estimates, especially those of heritability for intra and inter population selection and progeny mean performance, allowed to infer that the two single cross commercial hybrids derived populations are promising for use in intra and inter population recurrent selection programs. The magnitude of the estimate of additive genetic variance ( ) was large in both populations, showing the predominance of the additive effect in the control of the assessed trait. Although the populations presented variability and inbreeding depression, which are necessary conditions for dominance assessment, the estimates of dominance variance were negative in cases. On the other hand, the estimate of inter population additive genetic variance was of large magnitude. However, its partitioning in variance of the deviation of the intra and inter population additive effects ( ) and, also, in the covariance between these deviations and its additive effects ( ), did not allow conclusive inferences on the genetic properties of the two populations.
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