Photoperiod Response: Some crops require a specific day length in order to initiate flowering.
• Short day plants require a day length shorter than a specific period.
• Long day and intermediate day plants require a day length longer than a specific period.
Plant Genetics 101:
Genetic Integrity: To prevent varieties from crossing, seed producers must use some means of isolation (cages, distance isolation, time isolation, or hand pollination) during periods when pollination can occur. Genetic diversity within a variety is maintained by including a minimum number of randomly selected parents into the breeding population. This number will vary by crop species (See appendix page 2).
Ways to protect a varieties genetic integrity:
1. Properly identify and label plants.
2. Plant on clean land which has not been used to grow the
same crop in the past cycle.
3. Isolate plants from cross-pollination.
4. Plant at least 200 plants for cross-pollinated crops and 50-
100 plants from self-pollinated crops (this number varies
dependant on who you talk to).
5. Rogue off-types.
Rogue: A rogue is a plant which is “off-type” (different from the variety) or is otherwise undesirable. Rogue plants should be removed as soon as possible in order to protect the genetic integrity of the variety.