Use of the radicle emergence test (RE) to estimate germination and emergence potential in sponge gourd (Luffa aegyptiaca Mill.) seed genotypes

The study was carried out to test whether the radicle emergence (RE) test could be used to rank 12 Luffa (Luffa aegyptiaca Mill.) seed genotypes according to total (TG, %) and normal (NG, %) germination percentages in laboratory conditions (25°C, 14 days, dark), and mean germination time (MGT, day), seedling emergence percentage (SE, %), seedling shoot weight (SSW, g/plant) and hypocotyl thickness (HT, mm/plant) in climatic room conditions (23±2°C, 70% relative humidity), in peat moss medium after 15 days. RE (2 mm radicle) counts were made at 24, 48, 72, 96, 120 and 144 hours at 25°C in the dark after germination was set up. RE values were correlated to seed germination and seedling quality parameters. The highest correlation values occurred after 72h and onwards. RE 72h and seed quality parameters were regressed and were found to be significantly related to TG (R2=0.732, P<0.001), NG (R2=0.751, P<0.001), MGT (R2=0.842, P<0.001), SE (R2=0.754, P<0.001), SSW (R2=0.349, P<0.05), and HT (R2=0.757, P<0.001). The potential of the RE test to discriminate between Luffa genotypes according to their germination and emergence potential is discussed.