Effect of γ-rays chronic irradiation on soybean plants at VE-V1 stage

The effect of chronic irradiation on soybean seedlings was studied. The results showed that under 30 Gy and 50 Gy with the dose rate of 0.0146, 0.0051 per min respectively, the chronic irradiation evidently inhibited the growth, development and seed yield of soybean. Some variations which had never been appeared. In M1 generation one or three leaflets were observed frequently. In M2 generation, one or three cotyledons and unifoliolate leaf of soybean plants were observed at seedling stage. Some seedling were stunted with crinkled or linked cotyledons. The results also indicated that the dose rate of 0.0051 Gy per min had higher irradiation effect than the dose rate of 0.0146 Gy per min in same dose level. Chronic irradiation at VE-V1 (emergence-first node) stage could induce genetic mutation on protein content of soybean seeds. A mutant with 50.02 percent of protein was selected from progenies of M5 generation treated with dose of 50 Gy