Performance of maize genotypes of Rio Grande do Sul using mixed models

Abstract

The initial process for genetic gain in maize is obtained by identifying sources of variability in open pollinated populations. For the evaluation of these populations, statistical procedures as REML/BLUP analysis, has been increasingly employed by maize breeders. This study aimed to use the method of mixed models (REML / BLUP) for the estimation of genetic parameters and evaluation to a set of agronomic characters in hybrid genotypes, synthetic and landraces and verify its potential for breeding purposes and/or indicate their crop for small farmers in the Pelotas region. The characters evaluated were: tassel length (TL), tassel branch number (TBN), ear insertion height (EI), grain yield (GY), ear row number (ERN), kernels per row (KPR) and weight of a hundred grains (WHG). Were estimated by the mixed models of variance components by restricted maximum likelihood (REML) and the components of the prediction of the average, best linear predictor unbiased (BLUP). The best genotypes which presented final genotypic values superior to the general mean were the double hybrid COODETEC 308 for the characters TL, TBN, EI, GY and ERN; the single hybrid AS1551, triple hybrid AS3466 and synthetic BRS Planalto for TBN, EH, GY and ERN. Also, the populations Caiano Branco for TL, ERN and EI; Caiano Rajado for GY and ERN; Criolão for TBN and WHF; Dente de ouro for TL and ERN; Branco Roxo Indio for TL and WHG and Argentino Branco for TL and TBN. The genotypes BRS Planalto and Caiano Rajado show grain yield above the overall average and show promise for use by small and breeding programs.Additional keywords: genotypic values; grains yield; landraces; REML/BLUP; Zea mays L. ResumoO processo inicial para ganho genético em milho é obtido pela identificação de fontes de variabilidade em populações de polinização aberta. Para a avaliação destas populações, procedimentos estatísticos como análises REML/BLUP, têm sido cada vez mais empregados por melhoristas de milho. Este trabalho teve por objetivo a utilização do método de modelos mistos (REML/BLUP) para estimação dos parâmetros genéticos e avaliação para um conjunto de caracteres agronômicos em genótipos híbridos, sintéticos e crioulos de milho e verificar suas potencialidades para fins de melhoramento genético e/ou indicar seu cultivo para pequenos agricultores na região de Pelotas-RS. Os caracteres avaliados foram: comprimento do pendão (CP), número de ramificações do pendão (NRP), altura da inserção da espiga (AE), rendimento de grãos (RG), número de fileiras de grãos da espiga (NFE), número de grãos por fileiras (NGF) e massa de 100 grãos (MCG). Foram estimados via modelos mistos os componentes de variância pela máxima verossimilhança restrita (REML) e os componentes da predição de médias pelo, melhor preditor linear não viesado (BLUP). Os melhores genótipos superiores à média geral foram os híbridos CD 308 para os caracteres CP, NRP, AE, RG e NFE; AS 1551, AS 3466 e BRS Planalto para NRP, AE, RG e NFE e as populações crioulas Caiano Branco para CP, NFE e AE; Caiano Rajado...

Evaluation of resistance and stability of new sugar beet hybrids in field conditions infected with rhizoctonia root and crown rot disease

“…The lowest predicted WSY with a large distance from the total man was related to Rc9. The BLUP has been used in the evaluation of various crops such as rice (53), corn (54), cotton (55) and sugarcane (56) and useful results have been presented. One of the most important advantages of the mentioned method is the accurate estimation of the mean performance of genotypes, especially in LMMs (28,49,57).…”

February 2020

“…In this view, statistical models employed to estimate variance components and genetic parameters aid at elaborating the most suitable strategy for selection of traits of interest. Genetic parameters of the traits of interest may be estimated through the restricted maximum likelihood method (REML), providing reliable and applicable estimates to maize breeding (Baretta et al, 2016). The best linear unbiased prediction (BLUP) enables estimation of genetic values and to predict the next generation´s new means (Resende and Duarte, 2007), allowing to rank and select the most promising genotypes for traits of interest (Borges et al, 2010).…”

Restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) for analyzing the agronomic performance of corn

“…The need for robust and accurate models in evaluating complex experiments (multi-sites trials, multi-year trials), is making the mixed models-based on restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) more and more popular in plant breeding programs (Resende, 2004) due in many cases, the effect of local/year considered random, where the inferences are general (Piepho et al, 2007).REML/BLUP-based procedures are scarcely penalized by the non-additive nature of traits and by the experimental unbalance as compared to ANOVA-based models (Hu, 2015). In maize, these methods were effective in assessing the performance of hybrids and in accurate prediction of the variance components and breeding values Baretta et al, 2016).…”