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17 Cards in this Set
- Front
- Back
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open-pollenated seed
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fertile seeds
greater genetic diversity less conformity |
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hybrid seeds
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two inbred lines, crossbred for specific set of genotypes,
high conformity in original seeds saving the seeds and replanting -> sport controlled by ag business higher yields, higher fertilizer and water use |
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bulbs
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•plant parts used: bulbs (enlarged, non-photosynthetic leaves)
•how it works: bulbs spontaneously split •intervention required: none •works best in: naturally bulb-producing plants •occurs in nature? yes. |
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corms
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•plant parts used: corm (enlarged, non-photosynthetic stems)
•how it works: corms split naturally (or artificially) •intervention required: cutting •works best in: naturally corm-producing plants •occurs in nature? yes. |
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offsets
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plant parts used: short offshoots from main stem (branches)
•how it works: allow offsets to form; separate from main plant •intervention required: minimal •works best in: plants with naturally occurring offsets •occurs in nature? yes. |
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runners / stolons
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•plant parts used: long, skinny aboveground stems
•how it works: stolons extend outward, produce new shoots/roots •intervention required: none/minimal (plants can be induced to produce more offsets under stress) •works best in: naturally stolon-producing plants •occurs in nature? yes. |
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rhizomes
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•plant parts used: fleshy underground stems
•how it works: divide up rhizome •intervention required: none/minimal •works best in: naturally rhizome-producing plants •occurs in nature? yes. |
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cuttings: hardwood / softwood
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•plant parts used: twigs (with at least one axillary bud)
•how it works: crush the stem and/or treat with rooting hormone to promote root formation, bury it •intervention required: extensive •works best in: woody plants •occurs in nature: yes (e.g., shrub crushed by falling tree) |
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cuttings: leaf
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•plant parts used: leaf
•how it works: expose the cut leaf surface to soil and wait for root formation (hormone treatments sometimes applied) •intervention required: fairly extensive •works best in: certain herbaceous species (e.g. Gesneriaceae – African violets and their relatives) •occurs in nature? yes, in some species. |
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division
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•plant parts used: stem + root
•how it works: divide clumps of plants •intervention required: minimal •works best in: plants that form dense mats with multiple stems •occurs in nature: yes (e.g., plants partially eaten by herbivores) |
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layering, air-layering
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•plant parts used: branch tips
•how it works: root formation induced along a branch by keeping it in the dark, providing moisture, sometimes adding hormones •intervention required: extensive •works best in: woody plants •occurs in nature? yes (e.g., fallen branch under debris) |
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grafting
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•plant parts used: woody stem containing at least one bud
•how it works: wood implanted into a wound on host; vascular cambium fuses •intervention required: extensive •works best in: woody plants apples, pears, cherries, grapes •occurs in nature: no |
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tissue culture
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•plant parts used: meristem
•how it works: isolated meristematic cells in sterile culture are induced to divide; clones are treated with hormones to promote differentiation •intervention required: extensive. •works best in: almost any plant can be cultured, but some are easier than others •occurs in nature? no. -> all commercial bananas ++tissues are sterile; avoids transmission of bacterial or fungal pathogens |
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genetic engineering
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Often, combination of genotypes that would not naturally occur.
all living things share the same nucleic acids… so DNA from any species can be used by any other - plants lack animal immune system to reject "other" |
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how to make a gmo
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1. a plasmid (loop of bacterial DNA) is removed from the bacteria
2. a gene of interest is isolated from another organism 3. the gene is inserted into the plasmid 4. the plasmid is inserted back into the bacteria 5. bacterial cells bearing the genetically modified plasmid are isolated and multiplied - use antibiotics-resistance plasmid, then exposing bacteria to that antibiotic 6. the plasmid is injected into plant/animal cells |
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use of GMOs
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increase nutrient content of food
delay senescence, promote growth •increased cytokinin hormone production •not reduced abscisic acid –AA also controls stomatal closure… too little AA -> no stress tolerance increase stress tolerance of crops – heat, salt, drought, •incorporate substances that are toxic to insects (and not to humans) |
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risk of GMOs
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herbicide resistance in weeds
toxin resistance in pests genes could spread into natural populations horizontal transfer of antibiotics potential allergic reactions to GMO products intellectual property questions •loss of local control of food supply •loss of locally adapted genotypes agricultural industrial complex dominates policy |
