F₁ HYBRID PINEAPPLE RESISTANT TO BIALAPHOS HERBICIDE

Weeds are the main cost factor for pineapple production as at least a half of production costs are related to weed control. All current commercial pineapple cultivars are sensitive or susceptible to biodegradable herbicides. This research project aimed to establish an F1 hybrid pineapple cultivar resistant to herbicide by conventional breeding. Direct and reciprocal crosses between genetically modified ‘Phuket’ pineapple (TP) carrying the bialaphos-resistant (bar) gene and the commercial pineapple cultivars ‘Pattavia’ (PV) and ‘Phuket’ (PK) were made in 2005 at the Faculty of Agriculture, Rajamangala University of Technology Srivijaya, Nakhonsithammarat, Thailand. The crosses resulted in 1,172 F₁ seeds and 886 F1 seedlings were obtained from the first crossing of the two crosses. No seeds were obtained from selfing of TP, which shows that transforming ‘Phuket’ did not eliminate the incompatibility of TP×TP. The cross TP and PK also did not produce seeds but 14 seeds were obtained from the reciprocal cross of PK×TP showing that transformed ‘Phuket’ was at least somewhat compatible with the untransformed ‘Phuket’. The 886 F₁ plants were evaluated for agronomic characteristics, fruit quality and bialaphos herbicide resistance. There were 410 F₁ plants that showed resistance to bialaphos herbicide. Furthermore, there were 18 F₁ plants showing other good agronomic characters and good fruit quality. Three promising hybrids, (PV×TP)-51; (PV×TP)-46 and (PV×TP-34), showed resistant to biodegradation bialaphos herbicide, a °Brix of 18-22.2, a fragrant smell, crispy flesh and a smooth leaf with only the tip being spiny. In particular, (PV×TP)-34 hybrid plants had pale-pink bracts and fruit with a 22.2°Brix, cylindrical fruit shape, dark yellow flesh, and pleasant flavor. These potential hybrids will be propagated and evaluated to confirm the traits and subsequently released to farmers.