Time of acquisition desiccation tolerance in peanut seed during different growing stages was determined by evaluating seed moisture content, germination capability and electrical conductivity. It was done in research field of Gorgan university of agricultural sciences and natural resources in completely block randomize design in four planting date and four replications. Sampling was done weakly to harvest maturation. Seeds produced in each pod was transferred to laboratory and moisture content and standard germination was determined. Other part of seeds was dried slowly on air exposed condition and when it reached to 14-16 % of moisture content, standard germination test and electrical conductivity was done. According to the results, accumulation of seed reserves and seed moisture content declined gradually by 70 percent in the beginning stage of development to 30% in the later phase of accumulation reserves. Germination of freshly harvested peanut seed started when more than half of total storage substances accumulate in seeds and moisture content was estimated about 40-46 percent. But seed which dried gradually germination started after seed accumulated 17-20 percent of total reserves and this was coincide to beginning of acquisition desiccation tolerance in peanut seeds. Acquisition desiccation tolerance was started after 56-90 days after flowering and seed humidity was between 40-60 % based on fresh weigh. As results showed, desiccation tolerance was developed during 7 to 10 days and before accumulate less than 50 percent of total reserves in cotyledons that different planting date and subjected weather during plant growth stages could change it significantly.
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