Comparison of different selection methods in the seedling stage of sugarcane breeding

Danilo Eduardo Cursi; Mike C.Cox; Carina de Oliveira Anoni; Hermann Paulo Hoffmann; Rodrigo Gazaffi; Antonio Augusto Franco Garcia.

Family selection is an important procedure to be considered in the early stage of sugarcane (Saccharum spp.) breeding. Different approaches are available, but few comparative studies are performed in practice. The aim of this study was to evaluate the potential genetic gain when different selection strategies at early sugarcane breeding stages are considered. Two experiments involving the first and second selection stages of the Sugarcane Breeding Program of RIDESA/UFSCar were performed. In the first stage, three selection methods based on the concept of selection between and within families were applied to predict the highest genetic gain, i.e., BLUPi: simultaneously contemplates family and individual information for selection; BLUPis: promotes the dynamic allocation of individuals to be selected in each family; BLUPAUS: identifies high potential families and establishes differentiated selection intensities; additionally, mass and random selection methods were also performed. In the second stage, the selected clones were evaluated to compare the realized genetic gain. In the first stage, BLUPAUS had the highest predicted gain from selection (PGS; 12.7%) in TPH. BLUPis was highly correlated with BLUPAUS and was efficient. Moreover, BLUPi proved to be economically impracticable since phenotypic evaluations must be performed at the individual level. Family selection via BLUPAUS was equivalent to mass selection probably due to the low coefficient of genetic variation (CVg ≤ 15) among the families. However, the family selection strategy provides extra information for breeders that cannot be ignored; the possibility of studying the combining ability of genotypes for identifying promising parents for future cross combinations.