Eco-geographic variation of common wild rice - Oryza ru?pogon 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 has not being well documented despite a few of 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 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.

Functional trait diversity of wild rice species in Sri Lanka: implications for field identification and application

“…Journal of the National Science Foundation of Sri Lanka 49(3) 2010), thus differ in O. nivara habitats. The typical natural habitats of O. rufipogon were stream banks, marshy lands, swamps, and deep-water lake edges (Sandamal et al, 2018a). It grows in water 10 cm -5 m deep.…”

“…Information on habitat preference, geographical distribution and life history traits are the most important facts that drive efficient sampling of wild genetic resources in their natural habitats. Some of these habitats are threatened due to various human activities (Sandamal et al, 2018a). Therefore, immediate actions are needed to conserve these valuable rice genetic resources (Abhayagunasekara et al, 2018).…”

Phenotypic Characterization of Oryza nivara (Sharma et Shastry) Collected from Different Ecological Niches of Sri Lanka

“…The FL-PN-L and FL-A were the most variable traits for O. nivara in Sri Lanka. High population-based morphological variations were previously reported in other Oryza species in Sri Lanka, but no association was found between those traits and eco-geography [15]. The within-population variation for FL-L showed a relatively higher variation than that of among populations.…”

“…In particular, the wild species closely related to cultivated rice have a valuable gene pool and play a pivotal role in rice breeding programs by contributing genes resistant to biotic stresses and tolerance to abiotic stresses [2,5,11]. The species of the genus Oryza are widely diverse morphologically [12][13][14][15][16] and are genetically represented by distinct genome types, which provide a valuable opportunity to investigate variations of rice breeding programs [13,17]. Due to their high genetic compatibility with cultivated rice, species possessing the AA-genome are the most accessible genetic resources among the wild relatives [18].…”