Assessment of agronomic performance and prediction of genetic gains through selection indices in silage corn

Abstract

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); yield of grain ready for silage (GY); ratio of grains in the fresh weight (GFM) and fresh weight vield (FMY). The selection indices of Smith & Hazel, Willians, Pesek & Baker and Mulamba & Mock were used for gain prediction. The results showed that Mulamba & Mock provided the highest predictive values in the estimation of gains for the selection of hybrids. The topcross hybrids UENF-2205, UENF-2208, UENF-2209 and UENF-2210 presented the best performance and indicated high potential of TPWS, GY and GFM for silage production in the Northern and Northwestern Rio de Janeiro state.