Genetically modified (GM) crops, also known as genetically engineered crops, are plants that have been altered through genetic engineering techniques to exhibit desirable traits. These traits can include higher yields, resistance to pests and diseases, enhanced nutritional content, and improved tolerance to environmental conditions. The engineering process involves the insertion of specific genes into the plant's DNA, which allows the plant to produce proteins or other molecules that confer the desired traits.

1. Identification of Desired Traits:
The first step in engineering genetically modified crops is to identify the desired traits that the crop should possess. This can be done by studying the characteristics of existing crop varieties and identifying areas for improvement, such as increased resistance to pests or enhanced nutritional quality.

2. Selection of Genes:
Once the desired traits are identified, scientists search for genes that are responsible for those traits. These genes can be sourced from various organisms, including other plants, bacteria, or even animals. The chosen genes are isolated and prepared for insertion into the plant's genome.

3. Genetic Transformation:
The selected genes are inserted into the plant's genome through a process known as genetic transformation. There are several methods for achieving this, including using a bacterium called Agrobacterium tumefaciens or using a gene gun to directly insert the genes into plant cells.

4. Gene Integration:
After the genes are introduced into the plant cells, they need to integrate into the plant's genome. This integration process can occur randomly at different locations in the genome. Scientists use various techniques to identify plants that have successfully integrated the desired genes.

5. Plant Regeneration:
Once the genes have integrated into the plant's genome, the transformed cells are cultured in a laboratory to regenerate whole plants. This involves providing the cells with the necessary nutrients, hormones, and environmental conditions to stimulate their growth and development into complete plants.

6. Screening and Selection:
The regenerated plants are then screened and selected based on their ability to express the desired traits. This can be done through various methods, including DNA analysis, phenotypic observations, and laboratory testing.

7. Field Testing and Regulatory Approval:
Selected GM crop varieties undergo field testing to evaluate their performance under real-world conditions. The data from these trials are used to assess the safety and efficacy of the genetically modified crops. Regulatory bodies review the data and grant approval for the commercial cultivation and sale of GM crops if they meet the necessary safety and environmental standards.

Overall, the process of engineering genetically modified crops involves identifying desired traits, selecting appropriate genes, inserting them into the plant's genome, regenerating whole plants, screening and selecting for desired traits, and finally, obtaining regulatory approval for commercial cultivation.