Experimental strategies in carrying out VCU for tobacco crop I: plot design and size

Abstract

ABSTRACT. We aimed to establish standards for tobacco Valor de Cultivo e Uso (VCU) in Brazil. We obtained information regarding the size and design of plots of two varietal groups of tobacco (Virginia and Burley). Ten inbred lines of each varietal group were evaluated in a randomized complete block design with four replications. The plot contained 42 plants with six rows of seven columns each. For each experiment plant, considering the position of the respective plant in the plot (row and column) as a reference, cured leaf weight (g/plant), total sugar content (%), and total alkaloid content (%) were determined. The maximum curvature of the variations in coefficients was estimated. Trials with the number of plants per plot ranging from 2 to 41 were simulated. The use of a border was not justified because the interactions between inbred lines x position in the plots were never significant, showing that the behavior of the inbred lines coincided with the different positions. The plant performance varied according to the column position in the plot. To Experimental strategies for VCU in tobacco lessen the effect of this factor, the use of plots with more than one row is recommended. Experimental precision, evaluated by the CV%, increased with an increase in plot size; nevertheless, the maximum curvature of the variation coefficient method showed no expressive increase in precision if the number of plants was greater than seven. The result in identification of the best inbred line, in terms of the size of each plot, coincided with the maximum curvature method.

Estratégias Experimentais Para Avaliar O Milho Hibrido

“…Essas metodologias são empregadas frequentemente em diversas culturas, como cana-de-açúcar (Leite et al, 2009); melão (Dias, 2013); eucalipto (Mendes et al, 2014); tabaco (Toledo et al, 2013); mamão (Lima et al, 2007); sorgo (Lopes et al, 2005); milho (Cargnelutti Filho et al, 2011); café (Moraes, 2013) simulações, para cada tamanho de parcela, identificou-se a tendência da acurácia, sendo que o valor aumenta à medida que a quantidade de plantas em cada parcela aumenta. O comportamento desses dados resultou numa equação ajustada pelo modelo de Gompertz, e o possível ponto em que ocorre a mudança de curvatura é com 50 plantas, sendo de 0,70 a estimativa de acurácia seletiva média nessa condição.…”

“…Com as facilidades computacionais disponí-veis atualmente, os trabalhos de simulação tornaramse mais frequentes nos programas de melhoramento (Moraes, 2013;Toledo et al, 2013;Mendes et al, 2014). Uma das áreas em que a simulação ainda tem muito a contribuir é na avaliação de alternativas visando a melhoria da precisão experimental, entre elas a escolha do tamanho ideal das parcelas.…”

Experimental strategies for clonal eucalyptus

“…This methodology was applied with the aid of an algorithm that sorted out the plants (without replacement) in each plot of the experiment, to then perform analysis of variance of each simulated experiment. This algorithm was done in the software R and it was already used in another work with the same objective (TOLEDO et al, 2013). The simulated sizes began as of five plants.…”

“…Another option is to use a single large plot size and simulate different plot sizes from pre-existing data in the larger plot. This procedure has been used in other species (TOLEDO et al, 2013). Nevertheless, references to its use in the forestry sector were not found.…”

Progresso genético simultâneo: um exemplo de aplicação no melhoramento do tabaco

“…No Brasil, outros trabalhos, concomitantes a este, fomentam decisões relativas ao melhoramento da cultura. Toledo et al (2013) fizeram uso de simulação computacional com intuito de estudar a melhor configuração de forma e tamanho das parcelas nas fases finais de avaliação de genótipos. Outro estudo, almejou dimensionar a rede suficiente de experimentos finais de avaliação para conferir precisão na seleção/recomendação de cultivares (PULCINELLI et al, 2014, no prelo).…”