RELAÇÃO ENTRE A PERMEABILIDADE DA VAGEM E A QUALIDADE DA SEMENTE DE SOJA

The aim of this study was to evaluate the influence of pod wall permeability on the physiological quality of soybean seed. The cultivars studied were Sant'Ana, FT-2, FT-10, Bossier, Davis and the breeding line F 84-7-30, with a black seed coat. Pods were collected from plants at the R4, R5, R6, R7 and R8 development stages, which composed the treatments in regard to time of harvest. The parameters of permeability and the lignin content of the pods and the seeds within the pods were evaluated. The seeds were collected just after full maturity (R8), and the following tests were performed: germination, electrical conductivity, and tetrazolium, which determined seed viability and vigor. A randomized complete block design in a split-plot in time arrangement was used, with four replications per treatment. The soybean genotypes (six) composed the plots, and the split-plots consisted of the development stages (R4, R5, R6, R7 and R8). In seed evaluation, the same design was used, reducing the number of treatments to three in the split-plots (R6, R7 and R8). Pod permeability varied with the genotype and stage of development; this affected seed vigor, but not the viability of newly-harvested seeds. The pod lignin content did not show any influence on pod permeability.