EFICIÊNCIA DE ÍNDICES DE SELEÇÃO UTILIZANDO A METODOLOGIA REML/ BLUP NO MELHORAMENTO DA CANA-DE-AÇÚCAR EFFICIENCY OF SELECTION INDEXES USING THE REML/BLUP PROCEDURE IN SUGARCANE BREEDING

This study aimed to compare the efficiency of three selection indexes constructed from the estimated variance components and predicted genotypic values by the REML/BLUP procedure, on three first clonal populations in sugarcane. The populations were evaluated at the experimental area of the Sugarcane Research and Breeding Center – CECA of the Federal University of Vicosa, using the augmented block design. The traits number of stems per meter (NSM), average stem mass (ASW), total soluble solids content (BRIX) and production of BRIX per hectare (TBH) were evaluated in the cane plant and sugar cane ratoon-cycle in the A and B populations and the cane plant in the C population. The first three traits were used to construct the following selection indexes: classic index, multiplicative index and the index based on sum of ranks. The genetic-statistics analyses were carried by the GENES and Selegen - REM/BLUP programs. The multiplicative index showed higher selection efficiency as it presented larger coefficient of coincidence of genotypes selected with the selection strategy for TBH, larger direct gains from selection and larger indirect gains for TBH. However, the rate of selection efficiency of a certain index should be considered as an intrinsic characteristic of the studied population.