Seeds Flashcards
What is a seed?
An “immature plant in an arrested state” produced through sexual reproduction.
What is a “true-to-type” plant?
A plant that results from a seed has the same traits and appearance as the plant that produced the seed.
What is vegetative propagation?
A form of asexual reproduction of a plant where the stems, leaves, and roots, or other tissue not involved in reproduction are rooted.
What are synthetic seeds?
Seeds produced through tissue culture by the artificial encapsulation of somatic embryos, shoot buds, aggregates of cells, or any tissues that have the ability to form a plant.
What is a seed viability test?
Viability tests determine whether or not seeds are able to germinate under standard conditions and results are reported as germination percentages.
What is seed vigor?
A measure of how well seeds germinate rather than if they are simply viable or not.
How is seed vigor assessed?
By germinating seeds under adverse conditions and measuring how fast seeds germinate, how the seeds germinate at adverse temperatures or how seeds germinate after aging during short-term storage at elevated temperatures and moisture contents.
What is the purpose for a hot water soak treatment of a seed?
To treat brassicas and certain other species with hot water to kill most seed-borne fungi and bacteria without affecting the seed.
What are pregerminated seeds?
Seeds that have begun the germination process but have little or no root growth.
What is seed priming?
Seeds have been subjected to a controlled hydration process followed by redrying before planting by imbibing seed in either osmotic solutions, moist solid carrier materials, or with water alone to permit early metabolic events associated with germination to proceed before radicle emergence commences.
What seeds respond best to priming?
Peppers, tomatoes, and lettuce.
What factors determine seed longevity?
The combination of seed moisture content and temperature. 1 (Harrington, 1963). d
What is Harrington’s Rule?
Harrington’s Rule illustrates the relationship between seed moisture, temperature, and viability. It states that the potential storage life of seeds doubles for every 1% decrease in seed moisture content over the range from 5–14% or 5°C (41°F) decrease in storage temperature from 0–50°C (32–122°F).
How should seeds be stored?
As cool and dry as possible. As a general rule, the best moisture content for maintaining viability of most vegetable seeds is 5% and the best temperature below 5°C (40°F).
What is an heirloom cultivar?
One that was commonly grown during earlier times in human history, is not used for modern large-scale commercial production, has retained its traits through open-pollination and is not an F-1 hybrid.
What is an open pollinated cultivar?
A heterogeneous cultivar of a cross-pollinated crop that is allowed to inter-pollinate freely during seed production to produce plants reasonably true-to-type but by nature there is more natural variation in an open-pollinated than a self-pollinated crop. Many heirloom cultivars of cross-pollinated vegetables,
What is a self-pollinated crop?
A crop having perfect flowers that contain both male (anthers) and female (pistils) flower parts and therefore self-pollinated.
What is a pure line?
A self-pollinated crop that does not outcross because all the seeds were derived by self-pollination of a single flower, for example, lettuce or most beans. Pure line seeds are usually uniform and will grow true-to-type from seed..
What is a hybrid?
The offspring of sexual reproduction.
What are F1 hybrids?
Hybrids are made by sexually crossing two true-breeding homozygous plants to produce an F-1 (short for Filial 1), which means “first off-spring.” which are heterozygous, having two alleles, one contributed by each parent and typically one is dominant and the other recessive. The F-1 generation is also uniform.
What is heterosis?
F-1 hybrid vegetable cultivars express heterosis. or hybrid vigor which is expressed by F-1 hybrid cultivars expressed as the improved or increased function of any biological quality in hybrid offspring.
What is the dominance theory of heterosis?
The dominance hypothesis attributes the superiority of hybrids to the suppression of undesirable (deleterious) genetic traits from one parent over the other It attributes the poor performance of the inbred lines used to make F-1 hybrids to a loss of genetic diversity.
What is the overdominance theory of heterosis?
The overdominance hypothesis says that some combinations of alleles (which can be obtained by crossing two inbred lines) are especially advantageous when paired together in one individual.
Name three categories of commercial seeders?
Drills, plate planters, and precision planters.
What is fluid drilling?
Where germinated seeds are suspended in gel and transferred to a seedbed.
What are two types of transplants in terms of root systems?
Bare root or having a ball of soil and roots attached.
A rule of thumb for seedling depth is?
3 to five times the width of the seed.
What is the minimum acceptable greenhouse temperature for cold sensitive crops?
50 F
What is EC?
EC is electrical conductivity or total salts dissolved in water and is a measurement of water quality.
