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Taro {Colocasia esculenta) is one of the most important crops in the Pacific Islands. However, taro yields have been declining in Hawaii over the past 30 years due to diseases caused by oomycete and fungal pathogens. Chitin, an important structural component of the cell wall of most fungi, is hydrolyzed by the action of the enzyme chitinase. Plants transformed with a chitinase gene have shown increased resistance to several fungal pathogens. Oxalate oxidase, which converts oxalic acid and O2 to CO2 and H2O2 , has been shown to be involved in plant resistance to pathogens. Transformation of plants with an oxalate oxidase gene has increased their resistance to fungal pathogens. An efficient regeneration and transformation system of the taro cultivar Bun Long has been developed. Regenerable calli were induced on MS medium with 2 mg L-1 BA and 1 mg L-1 NAA (M5 medium). Multiple shoots from these calli were induced on MS medium supplemented with 4 mg L-1 BA (M15 medium). The rice chitinase gene (RICCHIll) was introduced into taro calli using particle bombardment. Analyses using polymerase chain reaction (PCR) and Southern blot confirmed the presence of the rice chitinase gene in one transgenic line. Agrobacterium tumefaciens-mediated transformation using two plant disease resistance genes: a rice chitinase gene (RICCHIl 1) and a wheat oxalate oxidase gene (gf2.8) were developed. Two hundred calli were infected with the supervirulent A. tumefaciens strain EHA105 harboring the plant transformation plasmid pBI121:RICCHI11. Six lines were shown to contain the rice chitinase gene using the PCR and Southern blot analyses. Transformation was also conducted using EHA105:pB1121:gf2.8 that contains the wheat oxalate oxidase gene gf2.8. Two independent lines were shown to be positive for the specific gf2.8 gene fragment using PCR, Southern blot and RT-PCR analyses, indicating the presence and transcription of gf2.8 gene in the transformed lines. In a preliminary bioassay, six transgenic taro lines with the rice chitinase gene exhibited tolerance to the fungal pathogen Sclerotium rolfsii. One transgenic taro line with the wheat oxalate oxidase gene showed tolerance to both the fungal pathogen Sclerotium rolfsii and oomycete pathogen Phytophthora colocasiae. To our knowledge, this is the first report of taro transformed with disease resistance genes. In addition, this is the first report of genetically engineered taro that exhibited disease tolerance in preliminary bioassays.

A model for the Hybrid Electric Vehicle (HEV) simulation has been developed with a specific power control strategy for an electric assist parallel configuration which is adopted by the UT-HEV NEON. A practical way of battery modeling is incorporated into this model. The model was developed on the basis of ADVISOR, which is a HEV simulation model developed at the National Renewable Energy Laboratory with different power control scheme and battery modeling. Some of the component modeling are adopted for the NEON model construction. By using the NEON model, the UT HEV NEON performance has been analyzed by parametric analysis of the vehicle components and power control parameter. The NEON simulation model implements a power control strategy by throttle position, also it incorporates fundamental features of HEV such as regeneration and regenerative braking. The model can also simulate the vehicle operation as a pure electric vehicle or as a conventional vehicle. The battery modeling developed yields accurate results without requiring information on the open circuit voltage (Voc) and internal resistance (R), which are generally not readily available. It is recommended from the simulation results that the APU used for the NEON should have a reduced power capacity in order to achieve the goal of HEV operation for most of the driving condition. The limit for the APU sizing is analyzed in light of the regeneration and ESS assist capability. Besides, the current throttle used should be down sized to about 70% of its current opening for the APU power control. A higher capacity battery would be beneficial in terms of SOC sustaining and extended EV range. Transmission effect on the vehicle regeneration capability and on the vehicle acceleration is analyzed with the two transmissions which have different gear ratio and identical speed and torque map. The choice of the transmission should be made based on the overall performance requirements. It is further recommended that vehicle tests on a dynamometer and road tests should be conducted for validation of the simulation results.