A study of the character and breaking methods of hard seeds in leguminous forages

To understand the character and breaking methods of hard seeds in leguminous forages, the character of hard seeds in 30 leguminous forages and the effects of three treatments including cutting seed coat, sulfuric acid, and hot water on seed rate, germination rate, and germination index were observed. The results indicated that the seed rate of the 30 leguminous forages varied from 0.00% to 96.67% with an average of 50.18%. The seed rates were significantly different among different leguminous forages and showed a significant negative correlation with their germination rates. There was a positive correlation between the optimal treatment time of sulfuric acid and hot water and seed rate for most of these seeds. When seed rate was more than 70%, the optimal treatment time of sulfuric acid and hot water was 15~30 and 7~15 min, respectively; however, when seed rate was less than 30%, the optimal treatment time of sulfuric acid and hot water was 5~10 and 1~3 min, respectively. Comparing with hot water treatment, cutting seed coat and sulfuric acid treatment were more effective breaking methods for most leguminous forages seeds. However, the germination rates of Galactia elliptifoliola and Crotalaria pallida were higher after hot water treatment than sulfuric acid. Therefore, to break hard seed, different treatments were effective for different species, and the optimal treatment time can be estimated based on their seed rate.