Salt Tolerance of 15 Rice （Oryza sativa L.） Varieties in the Office du Niger Zone of Mali

From 2003 to 2005, in pot and field experiments, rice response to salinity stress of 15 rice varieties was studied at germination and young seedling stages using salt affected soils collected from rice production areas in the Office du Niger zone of Mali. The rice varieties were composed of 10 rice genotypes from the breeding program of Mali and five from West African Rice Development Association （WARDA） program （Saint Louis, Senegal）. Soil samples were collected from the visually affected soils which were characterized by the appearance of white or black efflorescence on the soil surface. In pot experiments, the genotypes were allowed to germinate in both affected soil types （white efflorescence and black efflorescence） and salt effects on plant seedling growth were observed. Results showed that all varieties were significantly sensitive to salinity stress based on germination, young seedling shoot and root dry weights. Among the rice varieties, the most salt tolerant variety was BG90-2 （a high yielding geno