Diversity assessment of Philippine traditional purple rice (Oryza sativa L.)

Traditional rice varieties such as purple rice possess important genes that can be utilized in rice varietal improvement programs. The study was conducted to determine and evaluate the morphological, physico-chemical and genetic characteristics and disease and pest resistance of different purple rices of the Philippines and Malaysia. The collections were characterized using 28 morpho-agronomic characters and 16 microsatellite markers. Three major clusters with six subclusters were generated from quantitative data. The variety from Abra in Northern Luzon, Philippines was grouped in one cluster, while collections from Palawan, Surigao del Sur in Mindanao and Leyte in the Visayas were grouped in different clusters. Two main clusters were generated in assessing qualitative traits. Cluster A contains the 22 accessions and Cluster B contains the accession from Abra, which was singled out from all the other collections because it is the only accession with awn. The Shannon-Weaver diversity index revealed intermediate diversity (H'=0.64). Collections from different locations showed high variation while those from the same location showed; little variation. Seven collections from Palawan, Surigao del Sur in Mindanao, Bohol in the Visayas and Sabah, Malaysia were rated resistant to blast. The collections were also found to have higher percentage of protein (10-15%) compared to modern varieties (7-9%). Results showed low morphological variation among purple rice collections, however, molecular characterization revealed variation among the purple rices collected within and among provinces.. Fifty-three alleles were also detected and such variation could provide important genes for varietal improvement programs. Further collection of purple rice cultivars should be conducted in the country to fully assess the magnitude of their diversity.