Seed germination behaviour as influenced by physical and chemical treatments in Grewia tenax (Forssk.)

Grewia tenax (Forssk.) Fiori is a multi-purpose shrub indigenous to Indian Thar desert. It grows naturally in the wastelands, rangelands and other uncultivated lands during the rainy season, and provides green fodder to livestock for a longer period. It is a drought hardy shrub and can withstand harsh conditions of the climate and soil of arid regions. The seeds have strong dormancy which restrict its immediate multiplication and in nature it stands very sparse. The four-year-old seeds of G. tenax were subjected to nine different physical and chemical treatments to identify appropriate seed treatment method for higher germination. Treatment with 2% K2SO4 and 100 ppm Ethrel for 24 h recorded significantly higher germination percentage (77%) over control (30%), water soaking (33%), hot water treatment (40%), heat exposure of seeds at 40°C (47%) and soil burial treatments (47%). Seeds treated with 2% K2SO4 for 24 h started to emerge (first emergence) after 4.00±0.58 days of sowing as compared to the control seeds which showed 1st emergence after 8.67±0.33 days. Similarly, 50% emergence with the treatment achieved after 5.33±0.33 days of sowing for which control seeds took 13.33±0.1.4 days. The results of the study showed that dormancy of seeds could be overcome by treating with either 100 ppm Ethrel or 2% K2SO4 for 24 h.