CONTRIBUTION OF THE ADDITIVE GENETIC EFFECTS IN SOYBEAN BREEDING AIMING AT THE AGRONOMIC IDEOTYPE

Abstract

The development of new genotypes and their availability to the agricultural market is decisive for the success of the Brazilian soybean production chain. This study aimed to estimate the components of variance and genetic parameters of aspects of agronomic importance and to predict the selection of transgressive soybean populations and families based on the agronomic ideotype. The segregating families were conducted in an enlarged block design, composed of 285 F3 segregating families corresponding to the unusual treatments, and together with seven commercial cultivars assigned as common treatments, arranged in four replications. The characters of agronomic interest were measured the first pod insertion height, plant height, number of pods on the main stem, number of pods on the branches, pods containing only one seed, pods containing two seeds, pods containing three seeds, pods containing four seeds and seed mass. Were estimated additive genetic variance, genetic variance of the F3 segregating families, genetic variance of F2 segregating population, residual variance, phenotypic variance, narrow sense heritability, coefficient of determination for the effects of the F3 segregating family, coefficient of determination for the effects of the progeny, genetic variation coefficient, residual variation coefficient and predicted genetic ranking for the best F2 segregating populations and F3 segregating families. The pronounced additive genetic gains in the progeny showed higher values for the characters measured: first pod insertion height with 1.84%, for the family and population, the additivity presented the highest values for the number of pods with four grains. The selection of the progenies through the agronomic ideotype based on the greatest genetic gains of the morphological characters weighted by the largest seed mass will thus lead these populations to joint selection for the other yield components.