Human Interactions with Plants: Modification and Propagation Techniques

Focus on human interactions with plants, encompassing methionobotany, plant ecology, and conservation efforts.
Exploration of human modification of plants, specifically discussing Genetically Modified Organisms (GMOs) and transgenic plants.

Overview of methods by which humans propagate plants.
- Plant Breeding: A long-standing practice where humans alter plants, resulting in subspecies or cultivars.
- Artificial Selection: A key process in plant breeding. Example: Corn evolution from Teosinte, an ancestral plant resembling wheat, into the modern corn cultivated today.
  - Teosinte had fewer kernels per fruit compared to contemporary corn.

Agriculture: Originated around 10,000 years ago, marking a shift from hunter-gatherer societies to settled agricultural societies.
- Domestication of wild crops was pivotal to early civilizations.
Approximately 1% of vascular plants have been domesticated.
- Example: Brassicaceae family, resulting in diverse cultivars such as broccoli, cabbage, and kohlrabi.

Key Contributors to Human Calories: 60% of global human calories derived from three major crops: Wheat, Rice, and Corn, feeding approximately 4 billion people.
Expanding to 15 major food crops, nearly 90% of all human calories are sourced from:
- Potatoes, Sweet Potatoes, Cassava, Yams, Taro, Barley, Millet, Sorghum, Oats, Sugarcane, Soybeans, and various beans.

Focus on addressing food security concerns through various agricultural practices, including GMOs.
- Green Revolution: Major agricultural advancements post-World War II, emphasizing high-input agriculture.
- Usage of fertilizers, herbicides, and pesticides to enhance output and crop yields.
- Noteworthy figure: Norman Borlaug, known as the father of the Green Revolution, received the Nobel Peace Prize for his contributions to food availability.
Plan for sustainable practices in agriculture to prevent over-reliance on fossil fuels and maintain environmental health.

Pollination as a mechanism for sexual reproduction, critical in plant breeding.
Homozygosity: Resulting from self-pollination, which may lead to inbreeding and increased susceptibility to diseases (pests, viruses).
Diversity Introduction: Cross-pollination can increase heterozygosity, enhancing genetic diversity and resilience against environmental stressors.

Seed Saving: A method for maintaining desirable traits through selection of pure lines or open pollination.
- Preservation of heirloom varieties through seed banks (e.g., Seed Savers Exchange).
Hybridization: F1 hybrids are produced through crossing purebred lines, enhancing vigor and desirable traits.
Asexual Techniques Overview:
- Cuttings: Use of adventitious roots.
- Layering: Involves burying sections of a plant to promote rooting (e.g., tip layering, air layering).
- Grafting: Involves joining a scion (top part) to a rootstock (bottom part). Significant for pairing desirable fruit varieties with resistant rootstock.
- Micropropagation: In vitro cultivation of plant tissues in nutrient gels, facilitating large-scale production and conservation of endangered species.

Introduction to Genetic Engineering and emphasis on transgenic species, which incorporate genes from other organisms.
- Recombinant DNA Technology: Integration of genetic material from various sources.

1974: Creation of the first genetically engineered organism (an antibiotic-resistant bacterium) and the first genetically modified animal (a mouse).
1994: Launch of the first genetically modified food, the Flavor Saver Tomato, which contained genes to delay ripening for extended shelf life.

Gene Targeting: Techniques include gene knockout through electroporation and homologous recombination.
Gene Insertion: Utilizing Agrobacterium tumefaciens and E. coli for gene insertion into target crops.
Biolistics: Application of gene guns to deliver DNA-coated microprojectiles into plant cells.

Mechanism: Plants with inserted genes may confer resistance to herbicides like Roundup, allowing them to survive applications that kill surrounding weeds.
Inoculation process to select for modified cells involves applying herbicides, where only the modified cells survive, allowing further growth into embryos.

Discussion on commonplace GMO-derived products, indicating percent of crops that are modified (e.g., 90% of soy and canola).
Consideration of organic standards, where organic products are expected not to contain GMOs.

Pros and cons of genetic modification and implications for food security, biodiversity, and sustainable agriculture.