Marker-assisted Backcross Breeding in improving aerobic ability of weed competitive rice variety

Abstract

Rice (Oryza Sativa L.) is the staple food for more than half of the world population with at least two billion people in Asia, especially in South and Southeast Asia and Latin America (Rao et al., 2007). It is the third most important crop in Malaysia, grown mainly in eight granaries in Peninsular Malaysia covering an area of about 205,548 ha (MCA, 2007). Globally, weed is a serious constraint in rice production. Worldwide, the annual rice yield loss due to weed infestation is about 15-21% (Karim et al., 2004) and 10-35 % in Malaysia (Lo et al., 1990). According to Juraimi et al. (2011), weeds are mainly found under saturated and field capacity conditions. Meanwhile, water is a scarce resource nowadays due to uncontrollable human activities as well as the environmental factors itself. Water scarcity affects most plant activities. Juraimi et al. (2009) stated that, lower tillers number and shorter plants contributed to lower crop biomass under limited water condition. Hence, it is important to develop a rice variety that can withstand both water and weed stresses. To develop weed competitive rice varieties, it is crucial to identify the plant parameters that were responsible for the competitive ability that can be used as selection measures by plant breeders (Pester et al., 1999). Moreover, root is the important trait in extracting soil water for the plant growth under limited water condition. Therefore, the objective of conducting this experiment is mainly to introgressed suitable root trait markers into selected weed competitive rice variety by using marker-assisted Backcross Breeding Technique.