1. Introduction
Rice is considered one of the most important cultivated crops because it supplies food for one-half of the world-human populations and occupies the second rank for consumption after wheat [1]. Egypt is ranked 15 with 4,600,000 tons among the countries with the highest rice production, and is the biggest producer in the Near East region (world rice production, 2015). More attention is paid to the production of rice in the lower bay of the Nile River. However, due to limited water resources, rice cultivation has been limited in Egypt. Moreover, a dramatic loss of diversity in rice has been observed in the last centuries [2]. Therefore, producing new rice cultivars is urgently needed, not only to meet the demand of world population, but also to overcome such problems of abiotic and biotic stresses.