A quantitative assessment of germination parameters: The case of Crotalaria persica and Tephrosia apollinea

The present investigation attempted to assess the impact of seed pre-treatments on the germination of Crotalaria persica(Burm. f.) Merr and Tephrosia apollinea (L) Pers. Equally important was our investigation to quantitatively compare different germination parameters used for seed germination studies. The results showed that the final germination was highest for both species under chipping (CHIP), sand paper (SP) and 20 to 90 minutes in concentrated sulfuric acid (SA20 to SA90). Rubbing in sand (SAND) and water-soaking (SOAK) showed lower germination percentages. Mean germination time (MGT) was highest after 50 minutes in sulfuric acid (SA50) for both C. persica and T. apollinea. The coefficient of velocity of germination (CVG) was highest when seeds were treated with sulfuric acid during 30 minutes (SA30) for C. persica (56.1%) and during 60 minutes (SA60) for T.apollinea (66.8%). For the germination index (GI), chipping and all SA exposures (except 90 minutes) revealed high means for both C. persica and T. apollinea, while SP also resulted in high germination index for C. persica. The mean rate of seed germination was highest under sand rubbing and distilled water (0.9 and 0.8, respectively) for C. persica and under SA20 (1.3), for T. apollinea. The germination rate index (GRI) for C. persica was highest under CHIP, SP, and SA20 to SA60. Timson Germination Index (TGI) showed high values for most pre-treatments.The highest TGI recorded was 45.6% for SA30. As for the correlation between the germination parameters, it is recommended that final germination percent coupled with germination index are used as germination parameters. They do not require complex calculations, while they complement each other in giving a representative evaluation of seed germination.