Abstract:
Wild relatives of genus Oryza play an important role in rice breeding program worldwide. To
achieve sustainable crop improvement, wild relatives of rice are important as a genetic resource.
The objective of this study was to explore the promising traits in species identification to
distinguish wild rice species in Sri Lanka in terms of morphology. In this study, the rootstocks of
five wild rice species (O. nivara, O. rufipogon, O. eichingeri, O. rhizomatis and O. granulata)
available in Sri Lanka were collected from their natural populations representing different
ecological conditions. To search for variation patterns and distinguish features which can be
utilized for identification among species, plants were established in a common garden.
Morphological diversity was measured by 11 quantitative traits following rice descriptor of IRRI.
A considerable variation of morphological characteristics was found among the five wild rice
species for the most of the traits measured. The results of the analysis of variance indicated that
the total evaluated quantitative traits showed more variations among the species (P<0.05). The
significantly highest plant height (184.75 cm) with seedling height (100.00 cm), culm length
(152.25 cm) and culm diameter (7.3 mm) were showed in O. rufipogon. In contrast, O. nivara had
significantly the highest grain width (2.625 mm) and 100-grain weight (1.955 g) compared to
the other species. However, O. eichingeri and O. rhizomatis had a lower value of 100-grain weight
than the other species. Whereas both O. rufipogon and O. nivara exhibited, significantly the
highest flag leaf length and grain length than the other species. Moreover, flag leaf width of the O.
nivara and O. rufipogon were significantly lower than the other species. In contrast, O. granulata
had significantly larger flag leaf width (2.05 cm) but significantly the lowest plant height, culm
diameter, panicle length, and flag leaf length compared to the other species. O. eichingeri
exhibited significantly the shortest culm length (42.0 cm). Therefore, the morphological
diversity information of wild rice species could be useful in rice breeding program and species
identification in field level.
