Sarawak rice landraces as genetic resources for crop improvement: diversity, key traits, conservation and utilization—A review

Abstract

Asian rice (Oryza sativa L.)is fundamental to global food security, yet Malaysia’s rice self-sufficiency level (SSL) has declined to 69%, underscoring the need for breeding strategies that exploit locally adapted genetic resources. Sarawak is characterised by an exceptionally high number of indigenous rice landraces, including Geographical Indication (GI) cultivars such as Bario, Biris, and Bajong, collectively forming a broad and structured genetic base well suited for effective rice breeding. This review evaluates the breeding potential of Sarawak rice landraces by synthesizing literature published between 1980 and 2025, drawing on international databases and local grey sources. The reviewed research revealed extensive genetic diversity, with landraces forming multiple genetic clusters and expressing a wide range of agronomically valuable traits, including tolerance to drought, salinity, heat, and flooding, as well as resistance to major diseases such as rice blast. From a breeding perspective, these landraces represent promising donor resources for developing climate-resilient and yield-stable rice cultivars. Desirable quality traits, including aroma, pigmentation, and elevated antioxidant content, further highlight their potential for nutritional improvement and value-added breeding. However, the effective utilization of these genetic resources is limited by incomplete characterization, genetic erosion, and fragmented conservation and breeding efforts. Overall, the literature confirms that Sarawak rice landraces constitute a strategically important yet underexploited breeding resource. Integrating advanced molecular breeding approaches with participatory breeding, strengthened germplasm management, and supportive policy frameworks will be essential to translate this diversity into improved cultivars that strengthen long-term food security.