Morphological Relationships between Weedy Rice Morphotypes and Commercial Rice Varieties in Perak, Malaysia

Over the years, many rice morphotypes have appeared in paddy fields due to the autocratic nature of the rice plant. However, some of these morphotypes are problematic weeds and those which pose serious threat are commonly called as weedy rice (Oryza sativa L.) which has aggravated with the increase of direct-seeded culture technique (Ho et al., 1999). Besides, the presence of weedy rice in paddy fields is frequently the result of the predominant use of self-supplied seeds by farmers (Yu et al., 2005). It increases from season to season because weedy rice seeds shatter easily and are easily carried by wind and when touched by human or machines. It is well documented that weedy rice stands significantly reduce crop yields and quality in several countries of the world (Delouche et al., 2007). Recently, in Malaysia, weedy rice has been emerging as a serious weed in rice fields. According to Wah (1998), the production of direct-seeded land under rice cultivation is believed to be highest in Peninsular Malaysia amongst all the Asian countries. Currently, in Malaysia, agricultural areas cover 4.64 mha and approximately 14% (622,500 ha) of this area is dedicated to rice cultivation. There are eight granary areas as permanent rice producing areas (Itoh, 1991). Among these, Kerian (24,010 Abstract Art ic le History