Field Guide of Discovery-based Exercises for - Aseanipm ...

Exercise No. 3.17 88
VERNALIZATION OF RADISH SEEDS FOR ORGANIC
SEED PRODUCTION PURPOSES
BaCKGroUND aND raTIoNalE
Vernalization is a process by which seeds are subjected to
cold temperature treatment before germination to trigger
late flowering. Some vegetable seeds (e.g., cabbage, carrots,
celery, onion, and radish) need vernalization either to
de-activate inhibitory substances or activate stimulating
hormones necessary for their flowering. Cabbage will flower
if plants that have formed heads are exposed to a temperature
of 4.4 °C for 6-8 weeks. Celery will form seeds stalk if
exposed to a mean temperature of 4.4 °C to 10 °C for 10 days or longer 89 .
118
Field Guide of Discovery-based Exercises for Organic Vegetable Production
In the Cordilleras, farmers usually vernalize their radish seeds if they intend to use them for seed
production. Some farmers had tried different vernalization techniques to suit their location specific
conditions. If these learning experiences are shared among farmers in FFSs, then in this process,
their current techniques can still be further improved. This particular exercise was designed to
realize this objective.
How long will this exercise take?
• Thirty minutes for field walks, farmer interviews, and observations of fields planted to
vernalized radish seeds; and
• Thirty minutes to one hour hands-on and brainstorming session in processing area.
learning objectives
when is this exercise most
appropriate?
ɶ In FFS, TOT, and VST
sessions, before sowing
radish seeds in learning
field
ɶ When farmers want
to learn improved
vernalization techniques
for radish seeds from
other farmers
• To make participants aware of and understand that some organic vegetable seeds need
vernalization if they will be used for seed production; and
• To learn and do improved techniques shared by farmers in vernalizing radish seeds for seed
production.
88 Adapted from Callo, Jr., D.P., L.B. Teofilo, and H.A. Tauli (eds). 2002. Field Guide of Discovery-based Exercises for Vegetable IPM, Volume II. SEAMEO
Regional Center for Graduate Study and Research in Agriculture (SEARCA), Los Baños, Laguna, Philippines. pp106-108.
89 Bautista, O.K. (ed). 1994. Introduction to Tropical Horticulture. 2 nd Edition, SEAMEO Regional Center for Graduate Study and Research in Agriculture
and University of the Philippines Los Baños, College, Laguna, Philippines. pp381-402.