Intercruzamento em uma população de soja derivada de um retrocruzamento e perspectivas de melhoramento

Abstract

AGRADECIMENTOS A DeusAos meus pais, pelo exemplo de vida e pela força que me estimularam a crescer e me desenvolver como pessoa e como profissional.Ao professor Isaias Olívio Geraldi, pela amizade, orientação e ensinamentos.Márcia, Marco e Agnaldo e, em especial, ao Guilherme por todos os anos de companheirismo e amizade.Aos amigos do Departamento de Genética, que estiveram sempre presentes nos momentos de descontração e para dar um apoio nos momentos de dificuldade e, em especial, à Flávia e à Luciana, amigas para todo o sempre.Ao César pelo apoio e carinho indispensáveis para a conclusão desse trabalho. 8 9 EPÍGRAFE Se temos de esperar, que seja para colher a semente boa que lançamos hoje no solo da vida.Se for para semear, então que seja para produzir milhões de sorrisos, de solidariedade e amizade. Cora Coralina10 11 SUMÁRIO RESUMO. ABSTRACT Random mating in a soybean backcross population and breeding perspectivesThere is limited information on using random mating after backcrossing in soybeans. This work was carried out to evaluate the effects of one generation of random mating after backcrossing on the means, frequency distributions, genetic variances and responses to selection in a soybean population. The basic population was derived from a two-way cross between two inbred lines contrasting for grain yield and backcrossed to the higher yielding one. One hundred and seventeen progenies derived from a not random-mated backcross population (RC 1 F 2 progenies) and one hundred and eighteen progenies derived from a random-mated backcross population (RC 1# F 2 progenies) were evaluated in the 2008/09 growing season at Anhumas Experimental Station, of the Department of Genetics, ESALQ/USP, located in Piracicaba, state of São Paulo, Brazil. Evaluation trials were carried out using an 11x 11 quadruple lattice design (four replications). Plots consisted of 2 m rows spaced by 0.5 m, with 30 plants after thinning. The entries were harvested in bulks (which correspond to RC 1 F 3 and RC 1# F 3 progenies) and evaluated again in the 2010/11 growing season, using the same experimental design, plot size and location. The following traits were recorded: number of days to flowering (DF), plant height at flowering (AF), number of days to maturity (DM), plant height at maturity (AM), and grain yield (PG). The following parameters were estimated for both RC 1 and RC 1# : general mean, amplitude of variation, frequency distribution, genetic variance among progenies (