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

Selection indexes in the simultaneous increment of yield components in topcross hybrids of green maize

“…The classical index of Smith (1936) and Hazel (1943) showed a high-predicted genetic gain for CEYIELD, when weighted by weights 1, CVg, CVg/CVe, and h², with mean values of 19.20, 22.24, 21.22, and 21.28% respectively, which stood out as the greater predicted gains than the those of other indexes ( Table 2). Results of the present study corroborate those by Rangel et al (2011), Freitas et al (2013), Entringer et al (2016), and Crevelari et al (2018), who indicated positive genetic gains for traits of maize crop yield when using the index of Smith (1936) and Hazel (1943).…”

‘Tropical Sunki’ mandarin and hybrid citrus rootstocks under ‘Pera’ sweet orange in cohesive soil and As climate without irrigation

“…To assist the breeders' decision on the rootstocks with better overall performance, the rank sum index (Mulamba and Mock 1978) and the multiplicative index (Elston 1963;Garcia and Souza Junior 1999) were applied to the dataset of traits presenting significant differences between the evaluated rootstocks. Selection indices are frequently used in crop breeding programs, especially at initial stages, because several traits can be evaluated at once in a simple procedure to select superior genotypes (Crevelari et al 2018). Most evaluated variables presented CV% lower than 20% (Table 1), which is commonly reported in similar studies and adequate for using the proposed indices (Costa et al 2020;Crevelari et al 2018;Schinor et al 2013).…”

“…Selection indices are frequently used in crop breeding programs, especially at initial stages, because several traits can be evaluated at once in a simple procedure to select superior genotypes (Crevelari et al 2018). Most evaluated variables presented CV% lower than 20% (Table 1), which is commonly reported in similar studies and adequate for using the proposed indices (Costa et al 2020;Crevelari et al 2018;Schinor et al 2013). There was a positive correlation between the rank sum (I MM ) and the multiplicative (I e ) indices (r = 0.77**), indicating high degree of accordance and, consequently, a more reliable selection of the superior rootstocks.…”

UENF MSV2210 and UENF MS2208: Silage and green maize hybrids for Rio de Janeiro State, Brazil

“…The topcross hybrids were developed on an isolated field of the Experimental Station of Ilha Barra do Pomba-RJ. The topcross hybrids were selected based on the fresh matter yield, after four years of testing (Crevelari et al 2017, Crevelari et al 2018).…”