Isolation requirements for other certified seed Crop Minimum Minimum distance from Minimum distance from distance from any uncertified crop of the any other variety of the any certified crop variety or any other same kind where there is of the same variety of the same a difference of >4 weeks variety(m) kind(m) in time of flowering(m) Barley 3 3 3 Beans 3 3 3 Cowpeas 3 3 3 Groundnuts 3 3 100 Oats 3 3 3 Rice 3 3 3 Sorghums 3 200 100 Soya 3 100 3 Sunflower 800 800 800 Velvet- bean 3 300 3 Wheat 3 3 3 source: Copeland & McDonald, 1995 Wind vs insect pollinated plants: The former require shorter distances than the latter. For example: Isolation distance for certified seed of millets(cross-pollinated by insects) is 200m and that of grasses (wind pollinated) is 50 m. Temporal /Time isolation: - One crop is grown and timed to flower before other crops reach the reproductive stage - its advantage over distance isolation is that two crops can be grown/planted side by side and, therefore, facilitates seed production by small farms(no big requirement for distance isolation) - Requires irrigation facilities - There is no pressure for labor among different crop fields. Pea demand for labor is spread. Example: maize i) A single cross hybrid SC 701 commercial crop planted first, followed by an SC 701 seed crop planted 29 days later; the two crops must be separated by at least 10 barrier (border rows). Thus the two crops can be separated by about 10 m instead of about 163m (150 m plus 14 border rows). The approach is risky, 29 days may be too short, smaller commercial plants may result in late pollen shading. ii) An SC 701 seed crop planted first, followed by an SC 701 commercial crop planted 40 days later and the two crops must be separated by 10 male barrier rows. Possible reason for the above scenario ( more days required when seed crop is planted first than when it is planted second ) is the faster growth of the hybrid commercial crop
Isolation requirements for other certified seed Crop Minimum distance from any certified crop of the same variety(m) Minimum distance from any uncertified crop of the variety or any other variety of the same kind(m) Minimum distance from any other variety of the same kind where there is a difference of >4 weeks in time of flowering(m) Barley Beans Cowpeas Groundnuts Oats Rice Sorghums Soya Sunflower Velvet- bean Wheat 3 3 3 3 3 3 3 3 800 3 3 3 3 3 3 3 3 200 100 800 300 3 3 3 3 100 3 3 100 3 800 3 3 source: Copeland & McDonald, 1995 Wind vs insect pollinated plants: The former require shorter distances than the latter. For example: Isolation distance for certified seed of millets(cross-pollinated by insects) is 200m and that of grasses (wind pollinated) is 50 m. Temporal /Time isolation: - One crop is grown and timed to flower before other crops reach the reproductive stage - its advantage over distance isolation is that two crops can be grown/planted side by side and, therefore, facilitates seed production by small farms(no big requirement for distance isolation) - Requires irrigation facilities - There is no pressure for labor among different crop fields. Pea demand for labor is spread. Example: maize i) A single cross hybrid SC 701 commercial crop planted first, followed by an SC 701 seed crop planted 29 days later; the two crops must be separated by at least 10 barrier (border rows). Thus the two crops can be separated by about 10 m instead of about 163m (150 m plus 14 border rows). The approach is risky, 29 days may be too short, smaller commercial plants may result in late pollen shading. ii) An SC 701 seed crop planted first, followed by an SC 701 commercial crop planted 40 days later and the two crops must be separated by 10 male barrier rows. Possible reason for the above scenario ( more days required when seed crop is planted first than when it is planted second ) is the faster growth of the hybrid commercial crop
1297690222seed%20production-2011.docx