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

Exercise No. 7.03 246
SEED SELECTION AND SEED PRODUCTION
BY FARMERS FOR ORGANICALLY-GROWN
CROSS-POLLINATED (CUCURBITS) VEGETABLE CROPS
BaCKGroUND aND raTIoNalE
In the Cordilleras, local demand for seed materials of
horticultural crops is quite high. For vegetables, this is
evident in amount and volume of imported seeds. Plant
breeders or scientists from research institutions generally
identify the most appropriate species or varieties for seed
production. Traditionally, however, farmers themselves,
based from their experiences, identify appropriate varieties
in their specific areas. Again, although cultural management
practices of vegetable crops intended for seed production are
similar to those for fresh market; a few differences need
utmost consideration.
362
Field Guide of Discovery-based Exercises for Organic Vegetable Production
when is this exercise most
appropriate?
ɶ In FFS, TOT, and VST
sessions, when some
cross-pollinated vegetable
crops (e.g., cucurbits)
are grown for seeds in
learning field; and
ɶ When farmers want to
learn from other farmers
and do hands-on of
proper seed selection and
seed production of some
cross-pollinated vegetable
crops (e.g., cucurbits).
For cross-pollinated crops like cucurbits and crucifers, maintaining appropriate isolation distance is
important to maintain genetic purity by preventing unwanted pollination and unnecessary admixture
of seeds at harvest, especially when planting two cultivars of the same crop. The minimum isolation
distance for seed production is 400 m in cucurbits, and 1,000 m in crucifers. The presence of
pollinators (e.g., ants, bees, wasps, and flies) is necessary for cross-pollinating crops. In cucurbits,
assisted pollination, which involves collection of pollen from dehiscing male flowers and manually
introducing them on receptive female flowers of the same plant, is sometimes necessary to increase
fruit setting 247 .
Regular field inspection and roguing should be done throughout the life cycle of crop to remove
other crops or cultivars, noxious weeds, off-types, deformed or pest and diseases affected plants, and
other plants whose characteristics do not conform with desired cultivar at early and late vegetative,
flowering, fruiting, and harvesting stages. Many vegetable farmers use their own or their neighbor’s
previous harvests as seeds for next cropping.
246 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. pp 296-299.
247 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. pp167-177.