For optimizing rice grain yield under saline conditions; the current trail has been performed during 2009 and 2010 seasons at El-Sirw Agriculture Research Station, Damietta province, Egypt. The main objective of this attempt is to find out the response of six different rice varieties namely, Sakha101, Sakha102, Sakha104, Giza177, Giza 178 and Egyptian hybrid one (Sk2034H) to various phosphorous rates i.e. 0, 30, 60 and 90 kg P2O5 ha-1 under newly reclaimed saline soil. The experiments were performed in a split plot design with four replications where, rice varieties were arranged in the main plots and phosphorous rates were occupied the sub plots. The salinity levels of the experimental site were 8.0 and 7.50 dSm-1in 2009 and 2010 seasons, respectively with clay soil texture. Growth parameters, nitrogen and phosphorous leaf contents at heading as well as grain yield and yield attributing characteristics were measured at harvest.
The obtained results could be summarized as following, the tested rice varieties were significantly differed in their salt tolerance and in their response to phosphorous rates under saline conditions. Giza 178 and SK2034H hybrid one were the most salt tolerant varieties.
Phosphorous application significantly improved rice growth parameters (dry matter, LAI and chlorophyll content). Nitrogen and phosphorous leaf content were significantly increased by increasing phosphorous rates up to 90 kg P2O5 ha-1. Phosphorous application was found to be effective in enhancing rice grain yield and all yield attributing characteristics. Grain yield respond to P application up to 90 kg P2O5 ha-1, while most of yield component up to 60 kg P2O5 ha-1
Interestingly, the high yielding rice varieties in the terms of Giza 178 and Sk2034H significantly responded to application of phosphorous up to 90 kg P2O5 ha-1. In addition, the rest rice varieties were significantly responded to phosphorous application up to 60 kg P2O5 ha-1.
So, in case of newly reclaimed saline soil conditions, it could be recommended to grow Giza 178 and Egyptian hybrid one rice varieties under the same conditions with adding 90 kg P2O5 ha-1