Characterisation of Lowland Rice Landraces From the North-Western Region of Sarawak, Malaysia

Renee Priscilla Trawas, Sylvester Embuas (2025) Characterisation of Lowland Rice Landraces From the North-Western Region of Sarawak, Malaysia. Masters thesis, Universiti Malaysia Sarawak.

PDF MSc Thesis__Renee Priscilla Trawas.pdf Download (9MB)

Abstract

Oryza sativa L. or rice is Malaysia’s primary staple food and food crop. In Malaysia, rice is cultivated either as lowland type or upland type. Lowland rice is mostly cultivated in Malaysia due to high yield potential. Sarawak is known for its richness in rice diversity making the rice valuable for breeding material. However breeding using Sarawak rice are challenging due to little documentation has been made on varietal characterisation. The objectives of the current work were to find distinct morphological traits, anatomical traits and Simple Sequence Repeat (SSR) markers to delineate lowland rice landraces collected across four divisions in North-Western of Sarawak. Utilisation of Maturase-K (matK) was to assist in varietal discrimination. A total of 22 rice accessions was chosen. A set of 25 qualitative (QL) and quantitative (QT) morphological traits together with anatomical observation were used for characterisation. Further observation was conducted on S1 generation derived from 10 accessions, by observing the 25 morphological traits and anatomy observation on leaf samples with triplicates. Accessions in first generation showed genetic variations in all QL traits except for ligule and auricle colour. The S1 generation exhibited variations in QL traits, except for blade colour. The QT traits were helpful in characterising the accessions in both generations due to great variations they provide. Present study showed QL yield-related traits such as compact panicle type with presence of secondary branching have positive impact on number of filled grains. Accessions in present study recorded the same fundamental cell structure in leaf, midrib, root and stele. No variation observed in anatomical cell arrangement. Stomata density in S1 generation was found lower compared to first generation present study. Out of the 39 SSR markers, seven were polymorphic and cluster analysis was performed using Unweighted Pair Group Method with Arithmetic Mean. The number of alleles recorded was 18 with an average of 2.57 and mean Polymorphic Information Content recorded 0.67, suggesting the markers used were highly informative. Mean number of effective alleles was 1.61. The recorded Nei’s gene diversity (0.36) and Shannon’s Information Index (0.53) indicate low diversity in present study. The cluster analysis using seven SSR markers did not show clear clustering based on morphological traits nor origins. Phylogenetic analysis based on matK grouped all accessions into one cluster together with other accessions of O. sativa and O. rufipogon accessions. The phylogenetic tree based on matK showed clustering based on the genome type. Information collected from morphological and anatomical characterisation along with molecular analysis will provide basic information on Sarawak lowland rice. The information obtained are important for conservation of Sarawak rice germplasm and can be used in criteria selection for breeding attempt using Sarawak rice to ensure food security of the country.

Actions (For repository members only: login required)

View Item