Classificação da qualidade dos experimentos com cana de açúcar

• Autor(a) principal: Couto, Maurício Farias
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4025
• topic: Precisão experimental; Classes de coeficientes de variação; Seleção; Experimental precision; Classes of coefficients of variation; Selection; CNPQ::CIENCIAS AGRARIAS

The coefficient of variation as an experimental precision measure has been used for several crops. The present work had as general objective to evaluate the coefficient of variation and the selective accuracy as candidate statistics of experimental precision in essays with sugar cane. Specific objectives: (i) to propose classification ranges of coefficient of variation (CV) in experiments with sugar cane for several variables commonly used by this crop researchers; (ii) to establish adequate limits for the coefficient of variation, with applicability in experiments with sugar cane, considering the must used variables in the essays, through the classification criterion proposed by Costa (2002), taking into consideration the productivity differences along the cuts; (iii) to evaluate the coefficient of variation and the selective accuracy as experimental precision measures in experiments with sugar cane. The data were gotten from exhaustive bibliographic revision in scientific journals, from the sugar cane improvement program database of the Universidade Federal de Viçosa, master degree dissertations, doctor degree thesis and technical reports. Classification ranges were proposed according to the method of Costa (2002), which is based in the use of the median and the pseudo-sigma. The variables height and brix presented the smallest classification ranges of CV, followed by the number of stalks, Pol % of cane and ton of brix per hectare. The variables ton of cane per hectare (TCH), ton of pol per hectare (TPH) and weigh of the plot presented the larges.t classification ranges of the CV All variables presented specific classification ranges, making evident the necessity of considering, in the CV classification, the nature of the studied variable. For the limits of classification by cuts the used data were gotten from the sugar cane improvement program database of the Universidade Federal de Viçosa separated by cuts 1st, 2nd and 3rd. Classification ranges were proposed within each cut. The method proposed by Costa et al (2002) was used, which is based in the use of median and pseudo-sigma. There was disagreement to the specific classification ranges. This result makes evident the necessity of considering, in the classification of CV, the nature of the studied variable and the cuts. The variable TPH and TCH presented wider limits in the classification ranges by cuts. As the objective to propose a selective accuracy evaluation as candidate to the experimental precision classification in essays of the sugar cane genetic improvement program of the Universidade Federal de Viçosa. Analysis of variance were made for the sugar cane productivity data of 111 essays, and collected the values of the statistics: genotype mean square, error mean square, overall mean, value of the F statistic for genotype, and the experimental coefficient of variation. The following statistics were also estimated: genotypic coefficient of variation (CVg), experimental coefficient of variantion (CVe), coefficient of genetic determination between cultivars in the level of plot (h2) and selective accuracy (SA). For a safe inference, the F values for sugar cane cultivations must be equal or superior to 5.05, experiments with F values under 1.17 must be discharged, therefore they don t attend to the minimum accuracy. The SA presents itself as a possible candidate to classify experiments coming from the sugar cane improvement genetics program for taking into consideration the attributes, repetitions number, environmental variation and genetics, as became demonstrated in this work.