Marcadores morfológicos e moleculares na identificação e distinção de off-type em campos de produção de sementes de soja

Abstract

Morphological markers are useful tools for identifying off-type (atypical plants) in seed production fields. However, environmental factors can cause changes in certain individuals phenotype, turning molecular markers into useful tools for verification of possible genotypic differences between these individuals and the variety studied. The aim of this study was to evaluate the efficiency of SNP markers in identifying off-type based on genotypic and phenotypic (false positive) discrimination in soybean field production. Ten lines developed by Syngenta Breeding Program located in Cascavel-PR, Uberlândia-MG and Lucas do Rio Verde-MT were used. Each line was planted in its adaptation environment in the summer season / 2009-10. Data was collected from 22 morphological features for each line. After properly describing each line, field increases of these ten lines were carried out in Planura-MG, in the winter season / 2010. In the growth stages R6 and R7 the plants phenotypically atypical for each line were collected and evaluated, to which were considered only characteristics controlled by complex genetics. The DNA of the collected plants was analyzed using SNP markers. Twenty SNP assays were used, where each marker represented one soybean chromosome in order to cover the entire genome. Among the plants considered phenotypic off-type using visual morphological traits analyses, only 27.64% were confirmed by molecular tool as genetically distinct from the standard population, with a confidence interval between 19.7% and 35.5%. The use of molecular tools is effective for the discrimination of off-type genotypic and phenotypic (false positive) process due to environmental factors, preventing the write-off of seed lots that may meet the high genetic standards.