PJB-2019-883
PHENOTYPIC VARIATION OF WILD RICE (Oryza nivara) IN SRI LANKA
Asanka Tennakoon
Abstract
Genetic diversity of wild rice species in Sri Lanka has not been a well document, though it plays a key role in crop improvement programs of cultivated rice (Oryza sativa L.). The present study was carried out to identify the morphological variation pattern of the wild populations of O. nivara in Sri Lanka. Seven populations (P1 to P7) collected from different agro-ecological regions were characterized in a common garden based on nine morphological traits. The results revealed a high phenotypic variation among populations compared to that of within populations. However, flag leaf panicle neck length (FLPNL) and flag leaf angle (FLA) were the most variable traits while flag leaf length (FLL) was the least variable trait. Box plots clearly illustrated the overall patterns of the entire distribution of wild rice populations in relation to the morphological parameters. The cumulative values of the two principal components, i.e. FLPNL and FLA, explained 58.7% of the total variance. Populations from similar natural habitats clustered together. The P7 has adapted to intercept more sunlight by increasing flag leaf width (FLW) and FLA to compete with weeds and other shrubs, while P2 and P5 were the most closely related populations representing approximately similar ecological conditions of the dry zone. The P3 from the intermediate zone showed a vigorous plant growth with the highest (p<0.05) plant height, culm girth, and awn length. Knowledge of such morphological diversity would facilitate designing conservation strategies and basic information for proper utilization of wild resources in rice genetic improvement and breeding.
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