| dc.description.abstract | Twenty local rice varieties were identified showing moderate resistance reactions (Scale 3-6) during their seedling stage to colonies of biotype-1, biotype-2 and mixture of both biotypes of Brown Planthopper (BPH) in the laboratory. The varieties were further tested during their flowering stage of development to the BPH biotypes. The aim of the experiment is to determine weather rice plants showing moderate resistance in their seedling stage are also moderately resistant when they reach flowering stage or vice verca. This is important, since experience showed that the BPH caused hopperburn in any growth stage of susceptible varieties. Varieties having moderate resistance reactions in any stage of their development would reduce the threat of BPH for cousing hopperburn. None of the varieties tested showed moderate resistance reactions in both stages of their development to the biotypes of BPH. Paya Siam 8560 was found to be moderately resistant (Scale 4.66) in its seedling stage to biotype-1, biotype-2 and mixture of both biotypes of BPH, but as the plant becomes older they become susceptible. On the other hand, Paya Rumbiah 8558 was susceptible during its seedling stage, but showed moderate resistance reactions when they reach flowering stage. Crossing of both Paya Siam 8560 and Paya Rumbiah 8558 may be nescessary to obtain plants which would be moderately resistant in both seedling as well as flowering stage of the plant. Many more local germ plasms need to be tested for moderate reactions to the BPH biotypes in both their growth stages which would reduce the chance for hopperburn by BPH. | id |
