Domestication of Food Crops Student Notes PDF

The Domestication of Our Food Crops Objectives 1. Expand on the “centres of origin” by describing the domestication of wheat, rice, and maize 2. List the traits that constitute the domestication syndrome 3. Explain the importance of landraces in terms of genetic...

The Domestication of Our Food Crops Objectives 1. Expand on the “centres of origin” by describing the domestication of wheat, rice, and maize 2. List the traits that constitute the domestication syndrome 3. Explain the importance of landraces in terms of genetic variability 4. Explain the process of decreased genetic diversity in crop evolution 5. List the advantages and disadvantages to decreased genetic diversity in crops 6. Explain the advantages and disadvantages of hybridization of crops and their wild relatives 7. Explain autopolyploidy versus allopolyploidy 8. Explain how sequencing crop plant genomes can provide insight into plant evolution Wheat was domesticated in the Near East Rice was domesticated in _____and Western Africa  Maize and beans were domesticated in the ________________ The ancestor of domesticated maize (corn) is teosinte, which still grows wild in central Mexico Hybridization Hybridization with wild relatives led to crop improvement increase in genetic diversity and new traits (hybrid vigour) In some cases, has led to weeds that are difficult to control Domestication is accelerated evolution involving relatively few genes Domestication syndrome 1. Seed retention 2. Loss of seed dormancy 3. Increased yield 4. Loss of sensitivity to ____________ 5. Gigantism and diversity of harvested organs 6. Reduction in levels of toxic compounds Crop evolution was marked by genetic ________ that decreased diversity Genetic ___________: the loss of genetic diversity in a crop plant that develops as the introduction of higher yielding varieties displaces existing varieties Advantages and Disadvantages to decreased genetic diversity Crop uniformity Susceptibility to pests and disease What are your initial thoughts on GMO’s?  Polyploidy leads to new crops and new traits _________ : having more than two complete chromosome sets appear two ways: 1) autopolyploids 2) allopolyploids most mammals do not survive this, but plants often survive and become much larger, with larger edible parts. Polyploidy led to new crops and new traits The domestication of wheat resulted in diploid (Einkorn), tetraploid (durum or pasta wheat), and ___________(bread wheat) varieties How Crops are Genetically Modified Sequencing crop plant genomes provides insight into plant evolution  Golden Rice a genetically modified organism (GMO) whose genome has been modified in the laboratory in order to favour the expression of desired physiological traits or the generation of desired biological products recombinant genetic technologies were used to produce rice whose genome has been precisely altered at the molecular level by the inclusion of genes from an unrelated species that code for traits that would not be obtained easily through conventional selective breeding Next Class Term Test 2