Production Sites and Physiological Quality of Soybean Seeds.

Soybean seeds are produced in various states of Brazil and high levels of productivity have been achieved, especially in the Southeast and Midwest. However, several environmental factors such as temperature, relative humidity of air, altitude, pluvial precipitation and phytosanitary conditions have limited the obtainment of seeds with satisfactory physiological quality in some regions. Thus, this research aimed to evaluate the physiological quality of soybean seeds produced at different production sites. Five representative samples of soybean seeds, cultivar  M-SOY 7908 RR, from two different regions with distinct altitudes, Perdizes - MG (alt. 1030 m) and Casa Branca - SP (alt. 600 m), were evaluated by germination and vigor tests (first count of germination, accelerated aging, electrical conductivity and tetrazolium), as well as the verification of mechanical damage by sodium hypochlorite test, sanitary test, determination of the chemical composition of the seeds and seedling emergence in the field test. With the results of germination, first count of germination and tetrazolium (viability and vigor), it was possible to verify differences between the production sites studied. Seeds produced in Perdizes had better performance when compared with Casa Branca. The evaluation by the tetrazolium test allowed to identify minor moisture damage in seeds produced at higher altitudes, corroborating with reports found in the literature. Considering the other tests, no difference between the sites was observed, with exception of the accelerated aging test in which the classification of seed vigor was reversed. This may be due to the presence of fungi in the samples, which was relatively higher in Perdizes, being this problem avoided with seed treatment. Therefore, seeds with high physiological quality are produced in sites with high altitudes, and this condition should be considered in the production of soybeans seeds.