Abstract
This study was conducted to improve rice yield in saline affected areas in Africa using interspecific progenies. The salinity tolerance of an interspecific progeny NERICA 1 and its parents CG14 (O. glaberrima) and WAB56-104 (O. sativa) was examined in comparison with two Japanese upland rice cultivars. Plants were transplanted to 1.8 litter pots filled with the paddy soil, and grown under submerged soil conditions until maturity. NaCl (final concentrations were 100, 200 and 300 mM) was applied from 35, 49 and 63 days after sowing. Control plants were grown without application of NaCl. The salinity tolerance was evaluated based on the relative aboveground dry weight which expressed relative to the control. The salinity tolerance of WAB56-104 was similar to that of Japanese upland cultivars and CG14 was extremely sensitive, while NERICA 1 had intermediate salinity tolerance between its parents. The salinity tolerance decreased with the increase in shoot sodium concentration in all of the cultivars. The sodium concentration was high in CG14 since CG14 accumulated more sodium than the other cultivars under comparable salinity. Although NERICA 1 and WAB56-104 accumulated sodium similarly, the growing period, hence the duration of salinity treatment was longer in NERICA 1 than WAB56-104, resulting in a higher shoot sodium concentration in NERICA 1. These results indicated that NERICA 1 was tolerant to salinity more than the O. glaberrima parent which was sensitive to salinity, and NERICA 1 and the O. sativa parent responded to salinity stress similarly.
