Fábio Medeiros Ferreira

Relações fenotípicas e genotípicas entre componentes de produção em cana-de-açúcar

Phenotypic and genetic path analyses were carried out in order to quantify direct and indirect effects of production components on the variable ton of stalks per hectare (TSH) and mean stalk weight (MSW). Seventeen hybrid families were evaluated on a randomized complete block design with four replicates, at the Centro de Pesquisa e Melhoramento da Cana-de-Acucar - CECA of the Universidade Federal de Vicosa, Minas Gerais State. Planting was carried out in January 2000. The following variables were defined as production components: stalk height (SH), stalk diameter (SD) and stalk number (SN). The results indicated that the variables MSW and SN can be used for indirect selection of high yielding families, since they showed positive and high direct effects on TSH. Despite SH and SD showed high correlation with MSW, only SD showed high direct genetic effect on MSW, demonstrating the importance of this variable for indirect selection of families with higher mean stalk weight.

Capacidade produtiva e progresso genético de pinhão-manso

The objective of this study was to estimate genetic parameters and evaluate the genetic progress of Jatropha curcas L. agricultural traits from 2008 to 2011. Four Brazilian provenances were evaluated in a randomized block design using three replicates of 36 plants at a spacing of 3x2m. The number of bunches was one of the most important traits for grain production. The fruit ripening uniformity showed predominant environmental effect, being very limited the genetic progress to be achieved by plant selection. The estimated genetic progress with the selection of provenances may be considered low: 11%, 7% and 18% at 1th, 2th and 3th years respectively. The selection of the 30 best individuals within provenances provided a genetic progress of 29%. The genetic improvement of this oil crop should consider strategies to increase the genetic variability by breeding and introduction of new genotypes.

Análise dos coeficientes de endogamia e de parentesco para qualquer nível de ploidia usando o pacote estatístico R

ABSTRACT ANALYSIS OF THE INBREEDING AND COANCESTRY COEFFICIENTS FOR ANY PLOIDYLEVEL USING THE STATISTICAL PACKAGE R There are few softwares available to analyze relatedness among individuals and, to date, nonecan perform this analysis for polyploid organisms, with even number (2k) of chromosomes. This workimplements within package able to execute an analysis of relatedness for any 2k-ploidy level, numberof individuals (or populations) and number of generations in the pedigree. The main function, calc.rxy(),calculates the inbreeding coefficient (F X ) of each individual; coancestry coefficients (r XY ) between anytwo individuals; and average, variance, minimum and maximum of coancestry coefficient for each selectedindividual. A complete matrix of coancestry or any sub-matrix for selected individuals can be output. In ( 1 ) Recebido para publicacao em 1 de novembro de 2006 e aceito em 14 de maio de 2009.( 2 ) Departamento de Estatistica, Universidade Federal de Vicosa, 36570-000 Vicosa (MG). E-mail: peternelli@ufv.br.(*) Autor correspondente. Bolsista de produtividade em Pesquisa do CNPq.(

Selection among and within and combined selection in oil palm families derived from Dura x Dura

Oil palm, in view of the worldwide consumed oil, is a perennial crop of great importance. Nevertheless, the genetic improvement is still incipient. In this study we applied the selection among and within families and the combined selection, based on the phenotypic values and phenotypic performance (Pi statistic), to verify which strategy obtained the highest genetic gains. Five full-sib families were evaluated in randomized blocks, with five replicates and 12 plants per plot, over five years of successive harvests. The total number of bunches and the total fruit yield per year plant-1 were evaluated. Values of 1.00 and 0.25 for the ratio between the environmental variance among plots and the environmental variance among plants within the plot for both traits, respectively, were adequate for the estimation of the genetic parameters. The existence of genetic variability in the population Dura was verified for both evaluated traits. The combined selection, based either on the phenotypic values or on the underlying Pi statistic, resulted in the highest genetic gains. Despite the satisfactory gains since it translates the true yield potential of the evaluated genotypes and their performance stability.