COMPARATIVE STUDY ON HYBRID AND INBRED RICE UNDER DROUGHT AND SALINE STRESSES

The high heterosis displayed by hybrid rice might be exploitable for the enhancement of rice productivity in the presence of economically-important stresses such as drought and salinity. The current study aimed to find out the possibility of exploring hybrid rice under drought and salinity stresses. Rice varieties, Giza 177 and Giza 178 (inbred rice varieties) and SK2034H (the first hybrid rice released in Egypt) were tested under normal, saline and drought conditions using a split plot design with four replications. The investigation conducted under a controlled system in the greenhouse and field(Farm) of Rice Research and Training Center, Sakha, Kafr EL-Sheikh as well as at El-Sirw Agriculture Research Station i.e. saline soils, Egypt during two growing seasons of 2010 and 2011 in greenhouse and in 2011 under field conditions. The three rice varieties varied significantly in all estimated parameters and in their stress tolerance. The hybrid variety SK2034H was more tolerant to salinity and drought than Giza 178, the most tolerant Egyptian inbred rice varieties. This high capability of the Egyptian-developed hybrid might be mainly attributed to its greater root vigor, leaf area, flag leaf area, chlorophyll content, dry matter production, filled grains number, panicle number and weight; and lower sterility percent (sterility%). Furthermore, SK2034H had higher Na and K content than Giza 178, leading to a resulting in improved tolerance to stress. On the other hand, Giza 177 was more stress sensitive, possibly due to weakness of root system, poor growth, chlorophyll degradation, high Na/K ratio, and high sterility both stresses. The result obtained from saline soil and drought tested under field conditions came to confirm the obtained one under green house. Interestingly, both SK2034H and Giza 178 were at the same level for salinity tolerance, while SK2034H was more drought tolerant than Giza 178. stress. From the aforementioned results, SK2034H could be used on large scale especially under salt affected areas and in the end tail of irrigation canal.