Abstract:
Weedy rice is considered as one of the most troublesome, difficult-to-manage and economically damaging weed in Sri
Lanka. Weedy rice affects the growth, yield and quality of cultivated rice. However, weedy rice may contain important
genes which can be incorporated into the cultivated varieties. Therefore, study on morpho-physiological
characteristics of weedy rice are important to adopt efficient control measures and it may also be helpful to rice
breeders in developing new rice varieties. Therefore, this study was aimed to determine the morpho-physiological
diversity of weedy rice in Ampara district. Ampara, Akkareipattu and Lahugala locations from Ampara districts were
selected as sampling sites.Weedy rice populations representing locations were grown in a common field in a complete
randomized design with four replications. Plant height, thousand grain weight, own length, number of spikelet per
panicle, number of filling seeds per panicle, number of unfilled grains per panicle, number of shattered seeds per
panicle were measured and germination percentage and seed viability were tested. Significant variations were
observed in measured characteristics of weedy rice populations in Ampara District. Number of shattered seeds per
panicle showed the highest variability (CV-76.7%) compared to all the other characteristics. Significant differences
among three populations for all the measured characteristics except for plant height and viability percentage were
observed. Measured characteristic of Lahugala population were very similer to that of wild rice and significantly
differed from those from other two locations.
