Several mechanisms have been involved in the acquisition and maintenance of desiccation tolerance. Despite being genetically determined, the presence of these mechanisms can be intensified or reduced according to the drying rate of seeds or the environment in which the seed was developed. The absence or ineffective expression of one or more of these mechanisms determines the relative degree of sensitivity to desiccation. The objective of this research was to evaluate the biochemical aspects, as the á-amylase's activity and the electrophorectic patterns of the heat resistant proteins, and also the anatomical aspects of the seed pericarp, that could be associated with the high drying temperature tolerance. Seeds from lines, produced in 99/00, classified as tolerant and intolerant to high drying temperature, and seeds from hybrids which present significant reciprocal effect, produced in 00/0, were used. The seeds were harvested with 35% RH and dried at 45oC. Seeds dried under shadow were utilized as control in 99/00. The á- amylase enzyme was extracted from germinated seeds from each material in TRIS – HCl 0,2 M buffer, and the heat resistant proteins, of the embrionary axes, in TRIS – HCl 0,05 M buffer. Seeds that presented superior physiological quality, evaluated by the germination test, also presented greater band intensity for the á-amylase enzyme. A higher concentration of heat resistant proteins, of molecular weight between 18 and 44,1 kDa was verified, in seeds from the tolerant lines. The electrophorectic patterns of the heat resistant proteins were similar amid the hybrid seeds which presented significant reciprocal effect. Differences in seed tolerance to high drying temperature were related to the physical characteristics of the pericarp. Seeds from lines and hybrids that presented denser pericarp structure, formed by more compact cells, were more sensitive to high drying temperature.