MORPHOLOGICAL DIVERSITY OF WEEDY RICE ACCESSIONS COLLECTED IN AMPARA DISTRICT

Weedy rice is becoming common in most rice growing areas in Sri Lanka. It is variable in almost all the vegetative and reproductive characteristics and tends to have low tillering ability, easy shattering, long awns and higher dormancy in some variants. In addition, weedy rice may contain important genes which can be incorporated into the cultivated varieties. In order to ascertain the diversity for its possible utilization in rice crop improvement, morphological characters of weedy rice accessions were observed in three locations in Ampara district. Characters were observed from 50 individuals with at least 5m distance between plants. A significant difference was observed in weedy rice plants observed at Thottama for plant height while at Lahugala significant differences were observed for tiller number (3.22) and number of panicles (2.54). 58% of observed panicles had awns and purple colored long awns were the most prominent. In addition, white colored long awns, purple colored medium sized awns and white colored medium sized awns were present. The plants observed at Thottama showed higher number of panicles from relatively shorter plants. The existence of great diversity in the morphology indicates the presence of other related agronomic, physiological aspects for their selection and adoption

EVALUATION OF BROWN PLANTHOPPER Nilaparvata lugens (stal) RESISTANCE IN Oryza nivara WILD RICE ACCESSIONS FOUND IN SRI LANKA

Brown planthopper (BPH), Nilaparvata lugens Stal is one of the most serious rice pests in Sri Lanka. The study evaluated the nature of BPH resistance in seventeen O. nivara (WRAC 01, 02, 04, 07, 11, 12, 14, 19, 21, 22, 24, 25, 35, 41, 46, 62, and 9864) accessions collected from different locations in Sri Lanka using standard seed box screening test. Ptb 33(resistant), Bg 379/2, Bg 300(moderately resistant) and Bg 380 (susceptible) were used as check varieties. BPH culture maintained at the Rice Research and Development Institute, Batalagoda on Bg 380 was used for the test. BPH damage was scored (0-to-9 scale) according to the standard evaluation system for rice, developed by International Rice Research Institute. According to the results WRAC 04, 41, 25 and Ptb 33 recorded as resistant (score 0-3), WRAC 46, 35, 24, 22, 21, 14, 7, 2,1, 9864 and Bg 379/2 as resistant to moderately resistant (score 3.1-4.0), WRAC 11, 12 and Bg 300 as moderately resistant (score 4.1-5.0), WRAC 19 and 62 as moderately resistant to moderately susceptible (score 5.1-6.0), while no checked accessions were recorded as susceptible to the BPH indicating potential of using  Oryza nivara as a source of BPH resistance