Geographic variation of wild rice; Oryza nivara (S.D. Sharma and Shastry) populations in Sri Lanka.

Abstract

Wild relatives of rice are considered as an invaluable resource for crop improvement through restoring genetic diversity and incorporating useful traits back in to modern cultivars. In this context, phenotypic diversity of Oryza nivara populations exist in Sri Lanka were studied based on thirteen quantitative morphological traits. The results revealed high phenotypic diversity among O. nivara populations tested. Among the vegetative traits studied, a huge variability was observed for the plant height (138.70±6.1-93.00±3.0), leaf length (66.00±3.4-28.10±0.9) and seedling height (55.50±3.8-27.10±1.8). Among the reproductive traits observed, panicle length (31.5±0.3-12.2±0.3), panicle-bearing tillers/plant (25.3±1.2-11.7±2.5), number of spikelets/panicle (123±5.3-47±3.6), filled grains/panicle (98.7±3.1-16.3±1.5) and shattered seeds/panicle (105.33±7.6-44±1.7) showed remarkable variability among populations. The highest genetic identity was observed in between population-4 (P-4) from Matale district and P-7 from Baticaloa district (0.9182) while the lowest genetic identity value (0) was observed in between P-3 from Vavuniya district and P-10 from Matara district indicating the highest genetic distance among them. This study highlights the phenotypic diversity of O. nivara populations existing in Sri Lanka across the geographic locations and the potential of using them in rice improvement program in future.