During the dry season, the production of pastures is decreased, making farmers necessary to use corn silage as roughage source. Maize is increasingly recommended as the most important silage crop due to their qualitative and quantitative traits on top of the great acceptance for most animals. This work aimed to evaluate, through selection indices, the agronomic performance and prediction of genetic gains in corn hybrids for silage production. Eight topcross hybrids and seven controls were assessed in randomized blocks with six replications in two environments, in the municipalities of Campos dos Goytacazes and Itaocara -RJ, respectively, in the 2015/2016 agricultural year. The following agronomic traits were assessed: plant height (PH), height of first ear insertion (TH), stem diameter (CD), number of ears (NT), yield of ear with straw and ready for silage (TPS); yield of ear without straw and ready for silage (TPWS

During the dry season the production of pastures dicreases. Usually, it makes the situation necessary to use corn silage as fibrous fodder source. The aim of this study was to develop corn hybrids for silage production, prioritizing hybrid combinations of the heterotic group 'DENT' to better understand the association between the evaluated traits and to optimize the selection process by using selection indices. Nineteen topcross hybrids and five controls were evaluated in a complete randomized block design with four and five replications in the agricultural years of 2013 and 2014. The following traits were evaluated: plant height, first ear height, stem diameter, yield at silage stage, ear yield with and without straw at silage stage, fresh mass yield, and proportion of grains in the fresh mass. The highest coefficients of correlation were obtained between yield and ear yield with straw (r = 0.94**), and between ear yield with straw and fresh mass yield (r = 0.89**). The Mulamba & Mock selection index was used for prediction of genetic gains. For selection of the superior hybrids, the index resulted in higher estimates of predicted gains for yield at silage stage and fresh mass yield, with values of 6.13 and 4.46%, respectively, using weights assigned. The use of selection indices allows simultaneous prediction of gains in the two main traits. Topcross hybrids presented high potential for silage yield in the North and Northwest Regions.

The aim of the current study is to estimate the correlation coefficients and the consequence of genotypic correlations on direct and indirect effects through path analysis between agronomic traits of maize hybrids used for silage production. Eight (8) topcross hybrids and seven (7) checks were analyzed in completely randomized blocks, with six replications, in two environments: Campos do Goytacazes and Itaocara counties-Rio de Janeiro State, in the crop year 2015/2016. The following agronomic traits were assessed: plant height, first ear height, culm diameter, number of ears, ear yield with straw at silage maturity, ear yield without straw at silage maturity, grain yield at silage maturity, grains ratio in the fresh matter and fresh matter yield.

The aim of this study is to assess whether there is linear dependence between groups of morphoagronomic and bromatological traits in hybrid silage corn. Nineteen topcross hybrids and five checks were assessed in two different environments in Campos dos Goytacazes and Itaocara counties, Rio de Janeiro State, during the growing seasons 2013/2014. The study followed a randomized blocks design with four replicates. The phenotypic and canonical correlations between the groups of seven morphoagronomic and five bromatological traits were PLANT BREEDING -Article assessed. There is linear dependence between the group pairs of morphoagronomic, and bromatological variables. The morphoagronomic trait green mass yield can be adopted in indirect selection processes to indicate the increased bromatological quality of maize silage based on features such as crude protein, neutral detergent fiber, lignin, crude fat and mineral matter. Topcross hybrids UENF-2208 and UENF-2209 presented high potential for silage yield in the North and Northwest Regions.

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We studied the ontogenetic growth of goat wethers (castrated male goats) of the Saanen and Swiss Alpine breeds based on a large range of intraspecific body mass (BM). The body parts and the chemical constituents of the empty body were described by the allometric function by using BM and the empty body mass (EBM) as the predictors for morphological traits and chemical composition, respectively. We fitted the allometric scaling function by applying the SAS NLMIXED procedure, but to evaluate assumptions regarding variances in morphological and compositional traits, we combined the scaling function with homoscedastic (MOD1), and the heteroscedastic exponential (MOD2) and power-of-the-mean (MOD3) variance functions. We also predicted the ontogenetic growth by using the traditional log-log transformation and back-transformed results into the arithmetic scale (MOD4). We obtained predictions from MOD4 in the arithmetic scale by a two-step process, and evaluated MOD1, MOD2 and MOD3 by a model selection framework, and compared MOD4 with MOD1, MOD2 and MOD3 based on goodness-of-fit measures. Based on information criteria for model selection, heterogeneous variance functions were more likely to describe 10 over 36 traits with a low level of model selection uncertainty. One trait was predicted by averaging the MOD1 and MOD2 variance functions; and nine traits were better described by averaging the MOD2 and MOD3 variance functions. The predictions for other 16 traits were averaged from MOD1, MOD2 and MOD3. However, MOD4 better described 11 traits according to the goodness-of-fit measures. Depending on the variable being analyzed, the body parts and the chemical amounts exhibited the three types of allometric behavior with respect to BM and EBM, that is, positive, negative and isometric ontogenetic growth. Reference BMs, that is, 20, 27, 35 and 45 kg, were used to compute the net protein and energy requirements based on the first derivative of the scaling function, and the results were presented in reference to the EBM and EBM0.75. Both the net protein and energy requirements scaled to EBM0.75 increased from 20 to 45 kg of BM.

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This study described the main characteristics of the maize cultivars UENF MSV2210 and UENF MS2208. Adapted to the North and Northwestern regions of the state of Rio de Janeiro, they have a high agronomic performance and were developed for both silage and green maize production.