Abstract

                                Three species of wild rice and eight genetically diverse rice varieties were evaluated for resistance to Sogetella furcifera (Horvath) using seedbox screening test. The wild rice species. Oryza officinalis, O, latifolia and O.punctata and eight genetically diverse rice varieties viz., N 22 (Wbph1). ARC 10239 (Wbph2). Pth 33 (Wbph3). Podwi AS (wbph4), N'diang Marie (Whph5) IR 2035-117-3 (Wbph1+ Wbph2). Chaia Anaser (Wbphl+ Whph 3) and TN (no resistance gene) were included in the study. In the free choice screening test, wild rices maintained their extremely high level of resistance even after prolonged exposure to S. furcifera nymphs while plant damage ratings of cultivated rices increased progressively. The quantity of food ingested and assimilated by S. furcifera was significantly less on wild rices than on cultivated varieties. Compared to resistant varieties with diverse genes, S. furcifera caged on wild rices had slow nymphal development, reduced longevity and low fecundity. Egg hatchability was adversely affected on wild rices particularly on O. officinalis. Population growth was also less on wild rices. Steam distillate extracts of wild rices were more toxic to the first instar nymphs of S. furcifera than the extracts of resistant varieties with diverse genes.

Key words : Wild rice species, Resistance, Whitebacked planthopper