This research was continued from the Marker Assisted Selection (MAS) backcross breeding program for improve CNT1 to resist to BPH by introgressed a Bph3 resistant gene from K/R IL into CNT1. A population was already done in BC3F1. This study was attempted to develop BC4F1-BC4F3 and validated BPH resistance in improved lines. Two markers, RM170 and RM190 which linked to Bph3 gene and plant type were going together used for selecting the target plants. Twenty heterozygous BC4F1 and eighty three homozygous BC4F2 plants were selected. Finally, seventy seven BC4F2 lines carrying Bph3 were used for BPH evaluation with 3 BPH population from Phitsanulok, Tak and Pathum Thani. The results showed that almost improved lines were higher resistant to BPH than CNT1 and... |