Generation of transgenic plants by particle bombardment method results in multiple copy number as well as random integration of the transgene in the host genome. Both copy number and position have enormous effect on the expression and inheritance of the transgene. Low copy number, and stable expression is necessary for use of these transgenic lines in breeding programs. In this experiment we utilize four lines transformed with mtlD gene by particle bombardment. The aim of the experiment is to determine the copy number of the transgene and the expression pattern of the transgene under drought stressed and well watered conditions over T3 and T4 generations. Real-Time PCR was used to determine the copy number and was verified with Southern blot analysis. A known single copy gene (Puroindoline B) gene was used as the endogenous reference. The gene expression was studied using the Real-time reverse transcription PCR method. Beta-actin was used as the house-keeping gene for gene expression studies. Mannitol content of the leaf tissue was also measured by HPAE chromatography.