Assertion: Transgenic plant production is an application of plant tissue culture.
Reason : An organism that contains and express a transgene is called transgenic organism.

Both Assertion (A) and Reason (R) are correct  but R is not the correct explanation of A.

The correct answer is Option (2): Both Assertion (A) and Reason (R) are correct, but R is not the correct explanation of A.

Explanation:

• Assertion (A): Transgenic plant production is an application of plant tissue culture. This statement is correct. Plant tissue culture has various applications in different fields of biology. An example of this is the production of transgenic plants and animals. Transgenic organisms contain genes, which are transferred through the genetic engineering. These genes are known as transgenes.
• Reason (R): An organism that contains and expresses a transgene is called a transgenic organism. This statement is also correct. A transgenic organism is one that has been genetically modified by introducing a transgene, which is a gene from another species. The transgene is incorporated into the organism's genome and is expressed, leading to the production of a specific trait or protein.

Therefore, the correct answer is that both statements are correct, but the reason is not the correct explanation of the assertion.