Estratégias de seleção para qualidade de grãos em linhagens de arroz de terras altas

Abstract

The grain quality in rice is extremely important for breeding programs, in order to select lines that meet the standards demanded by the market. The quality attribute is composed by several characteristics, which can make difficult the work for breeder. Thus, the objective in this study was to verify the efficiency of the selection indexes in order to select upland rice lines that meet the grain quality standards. Fourteen lines of the Cultivation and Use Value test (CUV) of the upland rice breeding program of the Federal University of Lavras were evaluated. The experiments were conducted in the municipalities of Lavras - MG and Lambari - MG in the seasons of 2015/2016 and 2016/2017. The experimental was a randomized block design with three replications. The following characteristics were evaluated to compose the indexes: grain yield, minimum cooking time, water absorption index, grain chalkiness, integer grain percentage, grain length and width, apparent amylose content and gelatinization temperature. The following selection indexes were compared: Base index of Willians, Sum of “Ranks” of Mulamb and Mock, and Index Sum of Standardized Variables (Z Index) and also was held direct selection through grain yield. It was observed that the Base index obtained good gains with the selection for grain yield, but it was inefficient for the quality characteristics, results when used direct selection. The Ranks and Z index obtained superior and balanced gains for the characteristics, showing up more efficient in the selection of upland rice lines aiming at the quality of grains.