Rice (Oryzae sativa L.), belonging to the family Poaceae is widely
cultivated in most tropical and subtropical regions of the world (Ezuka and
Kaku 2000). Rice is one of the major food crops of the world especially of the
Asian countries like Bangladesh, Pakistan, India China, Vietnam and Korea.
More than 90% of the world’s rice is produced and consumed in Asia (Virmani
1996) and constitutes a staple food for 2.7 billion people worldwide (Salim et
al., 2003).