Inheritance of the Bialaphos resistance (bar) transgene was investigated by sexual hybridization of the transgenic pineapple cv. “Phuket” (TP) with the commercial pineapple cvs. “Pattavia” (PV) and “Phuket” (PK). Direct crosses, reciprocal crosses, and selfings were made in 2005 at Faculty of Agriculture, Rajamangala University of Technology Srivijaya, Nakhonsithammarat. A total of 2,437 F1 seeds, resulted in 1,459 plants were obtained from direct and reciprocal crosses of TP with PV and PK with PV. Of these, 1172 F1 seeds and 886 F1 plants were obtained from crossing between TP and PV. All selfed parental plants, and both direct and reciprocal crosses between TP and PK, either failed to set seed or set seeds with no kernels. β-glucuronidase (GUS) activity as conferred by the gus gene, was used in the initial screening for gene transfer into F1 plants at 2 cm in height. Of 253 from 886 plants obtained from sexual crosses involving PV and TP parents were checked for GUS activity and 116 were GUS positive while 137 were GUS negative, giving a ratio of 1:1 by a Chi-square test. When grown in pots, the GUS positive versus GUS negative F1 plants showed a corresponding 1 : 1 ratio of resistance to sensitivity when sprayed with the herbicide Basta™. The hemizygous transgenic plants bar/- transmitted the bar gene to the normal -/- (coin herewith as nullizygous) plants in the Mendelian manner. Thus the bar transgene can be fully utilized in the future conventional pineapple breeding programs. PCR analyses confirmed stable integration of the bar gene in F2 generation plants and reverse transcriptase-PCR confirmed active expression of the transgene in F2 plants. This research project also aims to establish F1 hybrid pineapple variety resistant to herbicide by conventional breeding. The 886 F1 plants were studied and evaluated for agronomic characteristics, fruit quality and bialaphos herbicide resistance. Of 886 F1 plants, 410 F1 plants showed resistant to Basta-X herbicide. Furthermore, there are eighteen potential F1 plants showing other good agronomic characters and good fruit quality. Three promising hybrids, (PV x TP)-51; (PV x TP)-46 and (PV x TP-34), showed resistant to biodegradation bialaphos herbicide, a high percentage of brix (18-22.2๐ brix), a fragrant smell, crispy flesh and a smooth leaf with only the tip being spiny. In particular, (PV x TP)-34 hybrids presented pale pink bract and fruit and it gave 22.2๐ brix, cylindrical fruit shape, dark yellow flesh, as well as pleasant flavor. These potential hybrids will further be propagated and evaluated to confirm the traits and consequently release to farmers.