Pods and kernels of two peanut(Arachis hypogaea L.) cultivars, a Shinpung type, Shindaekwangtangkong and a Virginia bunch type, Namdaetangkong were harvested periodically after the gynophore earthing in the field condition and their developments were monitored by observation of the changes in size, weight and moisture content. Seed germinability and seedling vigor were tested to set up a method for hastening the generation advancement in breeding procedure. Pods and kernels reached the maximum in size at 30 to 40 days after gynophore earthing and at that time the kernels had one hundred percent germinability and the seedlings sprouted from those kernels exhibited practically acceptable viability enough to grow for the next generation.