Seed viability testing provides valuable information for assessing seed lot germinability. However, most testing methods require destruction of seed prior to test. Because the dissected seeds for viability test cannot be used further evaluation, the nondestructively X-ray photography technique that can be applied for the evaluation of seed quality has been developed. In order to know the validity and accuracy of X-ray photography technique in seed evaluation test that conducted to remove the abnormal seed from a seed lot, we have compared the results from tetrazolium viability test, germination test and X-ray contrast method in cotton. Metallic salts treatment increased the efficiency of X-ray photographic method by enhancing the penetration of X-ray in abnormal or damaged seeds rather than normal seeds that have strong and well-organized tissues in seed. Cotton seeds presoaked for 16 hr in distilled water followed by soaking into metallic salt solution (5% NaI in water) for 60 min were easily classified seeds into dead seed and viable seed based on the radiography images obtained by X-ray radiation. We concluded that soft X-ray photography was reliable to find out the various defective characters due to heat and mechanical damage of seeds.

Several presowing seed treatments have been used to facilitate the seed germination and seedling emergence. The study was performed to design a model of presowing seed treatments in Taraxacum platycarpum. Germination and seedling growth responses to temperature, drying, chilling, GA3 and priming were investigated to know the optimum germination conditions and presowing treatment. The optimum temperature condition for germination and seedling growth were 15~20℃ at dark condition. The seeds exposed to infra red light, however, did not germinate. The moisture content of seeds dried at 35℃ for 3.5 hours was returned to the level of unimbibed seeds. The germination of seeds dried under dark condition was better than those dried under infra red light. Prechilling treatment imposed for 6 weeks showed higher germination rate than GA3 treatment or priming. In field test, the highest field emergence was observed in the seeds dried after prechilled for 6 weeks and followed by drying followed by GA3 〉 low temperature 〉 KNO3 priming. Imbibition with 0.1 mM GA3 solution for 2 hours then drying at 35 for 3.5 hour under dark condition was effective to the practical presowing treatment for Taraxacum seeds.