Search

Aiming to estimate the combining ability in tropical and temperate popcorn (Zea mays L. var. everta Sturt.) lines using multivariate analysis, ten popcorn lines were crossed in a complete diallel without reciprocals and the lines and hybrids were tested in two randomized complete block experiments with three replicates. Data were subjected to univariate and multivariate ANOVA, principal component analysis, and univariate and multivariate diallel analysis. For multivariate diallel analysis, variables were divided into group I (grain yield, mean weight of ears with grains, popping expansion, mean number of ears per plant, and final stand) and group II (days to silking, plant height, first ear height, and lodged or broken plants). The P2 line had positive values for agronomic traits related to yield and popping expansion for group I, whereas the P4 line had fewer days to silking and lodged or broken plants for group II. Regarding the hybrids, P2 x P7 exhibited favorable values for most of the analyzed variables and had potential for recommendation. The multivariate diallel analysis can be useful in popcorn genetic improvement programs, particularly when directed toward the best cross combinations, where the objective is to simultaneously obtain genetic gains in multiple traits.

When using genotypes of different heterotic groups, the scarcity of information on the inheritance of traits that are of economic importance to popcorn has hindered the implementation of more appropriate methodologies to obtain higher genetic gains. To date, the diallel of Hayman (1954) has not been used by popcorn researchers, but it has robust properties that can minimize this gap in scientific information. Therefore, ten popcorn lines were used to obtain 45 diallel hybrids, which were evaluated along with their parents and three controls in a randomized complete block design with three replicates at two different locations in the State of Rio de Janeiro, Brazil. Three agronomic traits of interest for the crop were scored based on the Hayman method (1954). The positive correlation between \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepacka...

In Brazil, using combining ability of popcorn genotypes to achieve superior hybrids has been unsuccessful because the local genotypes are all members of the same heterotic group. To overcome this constraint, 10 lines (P(1) to P(10)) with different adaptations to tropical or temperate edaphoclimatic environments were used to obtain 45 F(1) hybrids in a complete diallel. These hybrids and three controls were evaluated in two environments in Rio de Janeiro State. Grain yield (GY), popping expansion (PE), plant height (PH), ear height (EH), and days to silking (FL) were evaluated in randomized complete blocks with three replications. Significant differences between genotypes (Por= 0.05) were detected for GY, PE and EH. General combining ability was significant for EH, PH, PE, and GY, and specific combining ability was significant only for PE and GY. The most promising inbred lines that improved GY were P(3) and P(4), unlike P(8), P(9) and P(10), which improved PE, and P(2), which improved both PE and GY. The additive effects were much more important for PE than for GY. The hybrid combinations gave positive estimates of heterosis for GY but not for PE.

The aim of this work is to present the features of the popcorn cultivar UENF 14, developed from five cycles of recurrent selection of the population UNB-2U, to the scientific community. The cultivar produces yields of 3047.58 kg ha-1 and has popping expansion of 35.69 mL g-1. O presente trabalho tem como objetivo informar a comunidade científica os aspectos relacionados à cultivar de milho-pipoca UENF 14, desenvolvida a partir de cinco ciclos de seleção recorrente da população UNB-2U. A cultivar obteve produtividade de 3047.58 kg ha-1 e capacidade de expansão de 35.69 mL g-1.

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.