chapt 21- plants and people

What plant traits have been selected under domestication, especially in the cereals, and why?

Loss of Seed Shattering: Wild cereals naturally disperse their seeds by shattering, but domesticated varieties have been selected to retain seeds on the plant for easier harvesting.

Increased Seed Size: Larger seeds provide more food value and are easier to handle during planting and harvesting.

Uniform Germination: Domesticated cereals have been bred for consistent seed germination, ensuring synchronized growth and easier management.

Reduced Photoperiod Sensitivity: Domesticated cereals are less dependent on specific day lengths for flowering, allowing them to be grown in diverse climates.

Changes in Plant Architecture: Traits like shorter stems and compact growth reduce lodging (falling over) and make harvesting more efficient.

Improved Nutritional Content: Selection for higher protein or starch content enhances the food value of cereals.

What are the centers of domestication, when did they emerge, and how are the suites of crops similar or different among them?  

Fertile Crescent (Middle East):

• Crops: Wheat, barley, lentils, chickpeas.

• Traits: Early cereals with reduced seed shattering and larger seeds.

• Timing: Around 10,000 years ago.

Mesoamerica:

• Crops: Maize, squash, beans, chili peppers.

• Traits: Domestication of teosinte into maize; diverse suite of crops.

• Timing: Approximately 8,000 years ago.

Andean Region (South America):

• Crops: Potatoes, quinoa, tomatoes.

• Traits: Tubers and grains adapted to high-altitude conditions.

• Timing: Around 7,000–8,000 years ago.

Southeast Asia:

• Crops: Rice, millet, soybeans.

• Traits: Domestication of aquatic plants like rice.

• Timing: Roughly 8,000 years ago.

similar:

• Selection for traits like larger seeds, reduced bitterness, and easier harvesting

• Domestication often reduced genetic diversity in crops.

• Parallel evolution of domestication traits across regions.

Differences:

• Crop types varied based on local climate and geography

• Timing and pace of domestication differed due to cultural and environmental factors.

why are these geographic centers of domestication still important for contemporary crop breeding?

• Important for maintaining the contemporary crop

• regions harbor wild relatives and landraces of domesticated crops, which are invaluable for introducing traits like disease resistance, drought tolerance

• Studying crops from these centers helps breeders understand how plants adapt to specific environmental conditions

• Preserving the genetic diversity in these centers ensures a reservoir of traits that can be tapped into for future agricultural challenges

• regions provide insights into traditional agricultural practices and crop management

How has the history of spices been different to that of herbs, in general?

• Herbs are typically derived from the leaves or flowers of temperate plants

• spices come from seeds, bark, roots, or fruits of tropical plants

• Spices have historically been more valuable and sought after than herbs, often driving global trade and exploration

• Spices were often associated with wealth, status, and exoticism, used not only for flavor but also for preservation, medicine, and rituals

• Herbs were more commonly used for culinary and medicinal purposes within local communities.