Responses of Different Panicum miliaceum L. Genotypes to Saline and Water Stress in a Marginal Mediterranean Environment

The aims of this study were to evaluate: (1) the effect of sodium chloride (NaCl) and mannitol at different osmotic pressures on the germination of three proso millet (Panicum miliaceum L.) genotypes (VIR 9181, Unikum, and Kinelskoje) under controlled laboratory conditions; and (2) the effects of irrigation water salinity, maximum crop evapotranspiration (ETm) restitution regimes, and arbuscular mycorrhizal fungi (AMF) inoculation on forage production in a marginal Mediterranean soil for the genotypes that showed the highest and lowest seed germination. In the laboratory experiment, the Unikum genotype showed the highest seed germination (95.1%), whereas the lowest was found for Kinelskoje (80.4%). Regardless of the osmoticum type, germination was significantly reduced by osmotic pressure increases. Unikum showed a higher fresh biomass yield (FBY) (620.4 +/- 126.3 g m(-2)) than Kinelskoje (340.0 +/- 73.5 g m(-2)). AMF inoculation did not influence FBY under salt conditions, while in the absence of salt conditions it significantly increased the Unikum FBY (+50.7%) as compared to the uninoculated treatment (552.5 +/- 269 g m(-2)). The 25% ETm significantly reduced FBY in both genotypes (-86.2% and -84.1% for Unikum and Kinelskoje, respectively) sd compared to the 100% ETm treatments (1090.3 +/- 49.7 g m(-2) in Unikum and 587 +/- 72.2 g m(-2) in Kinelskoje). The obtained results give novel information about proso millet forage production in low-input agriculture in marginal semi-arid Mediterranean land.