Genetic gains in the UENF-14 popcorn population with recurrent selection.

The popcorn breeding program of Universidade Estadual do Norte Fluminense Darcy Ribeiro aims to provide farmers a cultivar with desirable agronomic traits, particularly with respect to grain yield (GY) and popping expansion (PE). We evaluated full-sib families from the seventh cycle of recurrent selection and estimated the genetic progress with respect to GY and PE. Eight traits were evaluated in 200 full-sib families that were randomized into blocks with two replicates per set in two contrasting environments, Campos dos Goytacazes and Itaocara, located in north and northwest Rio de Janeiro State, respectively. There were significant differences between sets in families with respect to all traits evaluated, which indicates genetic variability that may be explored in future cycles. Using random economic weights in the selection of superior progenies, the Mulamba and Mock index showed gains for PE and GY of 5.11 and 7.78%, respectively. Significant PE and GY increases were found when comparing the evolution of mean values of these two parameters that were assessed at cycles C0-C6 and predicted for C7. Thus, an advanced-cycle popcorn cultivar with genotypic superiority for the main traits of economic interest can be made available to farmers in Rio de Janeiro State.

Diallel analysis of corn for special use as corn grits: determining the main genetic effects for corn gritting ability.

Corn grits are used for various purposes such as flakes, snacks, livestock feed, hominy, extruded products, beer, etc. The grit size proportion varies according to the hybrid, and thus, once the use of the grits is linked to the particle size, determining the genetic effects is essential to develop hybrids for any specific use. For this purpose a complete diallel series of crosses, involving eight parents, was performed near Maringá, PR, Brazil. The objective of this study was to evaluate the general (GCA) and specific (SCA) combining abilities of 28 progeny for selection of hybrids for breeding programs and extraction of inbred lines for hybrid development. The response variables, such as plant height, ear insertion height, crop stand, grain yield, and grits, small grits and bran production, were gauged and appraised for each of the 28 progeny. The trait effects and GCA were significant for all response variables, while for SCA, only grain yield and crop stand showed significance (P < 0.05), according to Griffing (1955) analysis. A significant weak negative partial correlation was found between grain yield and grits conversion. In relation to the hybrid selection for breeding programs, the parent IAC Nelore was highly recommended for recurrent selection and the hybrids IPR 119 x HT 392 and IAC Nelore x HD 332 for the extraction of pure lines for hybrid development.