Germination responses of Sporobolus ioclados: a saline desert grass

Sporobolus ioclados (Nees ex Trin.) Nees (Poaceae), a halophytic grass distributed in coastal and inland regions of Pakistan, is a potential forage crop which could be grown in the degraded saline soils of the Indus plain and coastal areas. Greatest germination was obtained in non-saline control and it was linearly reduced with increases in salinity to 500 m NaCl. Variation in temperature substantially affected germination in both the saline and non-saline treatments. At the optimal temperature regime of 20:30°C, S. ioclados seeds showed 93% germination at 0 m NaCl and 18% germination at 500 m NaCl, respectively. In all other temperature regimes, only 50% of the seeds germinated in 0 m while none germinated at 500 m NaCl. Rate of germination decreased with an increase in salinity at all temperature regimes but comparatively higher rates were obtained at 20:30°C. Seeds showed a low recovery response when transferred to distilled water after 20 days of exposure to salinity and tetrazolium viability test showed that most of the un-germinated seeds were dead. The present study showed that if the seed is protected from salinity and temperature stress during storage in the soil, it could germinate during monsoon rains.