Eco-geographic Variation of Common Wild Rice Oryza rufipogon Griff. in Sri Lanka

Abstract

Wild species of rice (Oryza) have superior agronomic characteristics to be incorporated in rice breeding programs worldwide. Population studies of wild relatives of rice in Sri Lanka have not been well documented despite a few attempts. In the present study, phenotypic diversity of Oryza rufipogon populations exist in Sri Lanka were characterized based on nine quantitative morphological traits. Populations (P1, P2, P3, P4 and P5) were established in a common-garden and were characterized. The results revealed moderate phenotypic diversity among O. rufipogon populations studied. However, flag leaf length and awn length were the most variable traits while plant height, flag leaf angle, flag leaf panicle neck length and spikelet angle were the least variable traits. O. rufipogon can be simply distinguished using flag leaf length and width, panicle branching type and distance from panicle base to lowest spikelet insertion. The dendrogram results indicated that four main clusters are at a similarity level of 98.73, showing the diversely related populations with a high identity based on higher similarity values. P1 and P2 populations grouped together by forming the first cluster. The second, third and fourth clusters consisted of P3, P5 and P4 populations, respectively. One population from the first cluster and P3, P5 and P4 populations can be used for conservation. This study highlights the phenotypic diversity of O. rufipogon populations existing in Sri Lanka across the geographic locations and Knowledge on such morphological diversity provides opportunities to design conservation strategies and the potentials of using particular population based on breeding objectives.