Effect of temperature and PEG treatment on germination and seedling length of corn and soybean varieties

Germination and seedling growth of corn (Zea mays L. Vars. KS 16, KS 6, KS 15, Suwon 19, Ga 209. KS 5, Jinjuok, and Hoengsongok) and soybeans (Glycine max. (L.) Merr. Vars. Bangsakong, Hill, Danyupkong, Paldalkong, Baegwunkong, Kwangkyo, Hwangkeumkong, and Changyupkong) were measured at two temperatures (15 and 30deg C) and ten polyethylene glycol (PEG) treatments. These PEG treatments were 20, 25 and 30g/100ml H2O of PEG 6,000, PEG 10,000 and PEG 20,000 molecular weight (MW), including untreated control. Observations were taken at 4 days for treatments at 30deg C and 12 days for those at 15deg C. Twenty seeds of each variety of corn and soybeans were placed on Whatman No. 1 (12cm) filter paper in glass petri-dishes, and adjusted to 20ml of the proper treatment solution supplemented with 0.2 percent thiram using automatic syringe. The dishes were covered with cap and sealed with parafilm. The seeds were germinated at a constant temperature of 15 or 30deg C under dark conditions for programmed period. Seedling moisture content of corn was lower than that of soybeans both at 15 anel 30deg C. However corn showed greater seedling length than soybeans at temperatures of 15 and 30deg C Seedling moisture content and seedling length of corn and soybeans were reduced as PEG concentration increased from 20 to 30g/100ml H2O at PEG 6,000, PEG 10,000 and PEG 20,000. But no significant differences were found on seedling moisture content and seedling length of corn and soybeans among PEG 6,000, PEG 10,000 and PEG 20,000. Varietal differences in seedling moisture content and seedling length of eight corn and soybean varieties were observed with PEG treatments. Corn variety Jinjuok and soybean variety Paldalkong showed the greatest seedling length among eight varieties of corn and soybeans. The results of this study indicated that germination test of corn and soybean seeds in aqueous solutions of PEG 6,000, PEG 10,000 and PEG 20,000 showed similar for moisture stress simulation and has potential for screening varieties improved emergence ability during moisture stress