Caracterização de linhagens endogâmicas recombinantes em arroz

Abstract

Rice is a crop that has great economic importance, especially in Rio Grande do Sul, being responsible for almost 70% of national production. Breeding programs increase efforts to identify superior genotypes with desirable agronomical traits, using methods such as hybridization, which aims to form segregating populations and increase genetic variability. The identification of superior genotypes is a complicated task, especially because the traits of agronomic importance are quantitative, controlled by a large number of genes and highly influenced by the environment. Thereby, the strategies to verify the population genetic variability, the prediction of the truly heritable fraction and the gain by selecting the target trait become promising and valuable tools for rice breeding programs. This study aims to analyze the distribution of rice progenies regarding genitors, to verify the possibility of identifying transgressive families to plan and direct future selections with the help of the gain by selection and trait heritability. Reciprocal crosses between BRS Querência (Oryza sativa sp. indica) and Nipponbare (Oryza sativa sp. japonica) were performed, generating 121 and 160 hybrid F1 plants of each cross and the generation advances conducted in the experimental field of Embrapa Clima Temperado (ETB), Capão do Leão – RS, to the F6 generation, together with parents. The design was incomplete blocks with intercalated checks in four replications. With the crosses, it was possible to get transgressive segregating families in both directions for all analyzed characters, and the cross using Nipponbare as female allows greater segregation. The F10 family from the cross N x Q, and the F36 family from the cross Q x N, were superior and should be further evaluated in trials.