| Agricultural extension |
|Providing agricultural support services|
The quantity and quality of seed is one of the most limiting factors in crop production. It is essential that small-scale farmers gain access to necessary amounts of high quality seed if they are to realize profitable yields. Yields are a function of many factors, two of which are variety (the type of seed) and seed quality. (See TOOLS for checklists of "Factors To Consider in Evaluating Seed Variety", and for "Guidelines for Selecting Quality Seed".) Because adequate quality seed is not often available to farmers in developing settings, extensionists may have to multiply or at least help farmers grow their own seed.
There are generally four variety types:
These are the varieties most village farmers use. Local varieties' advantage include:
• farmer familiarity with their characteristics and needs
• fair to good resistance to local insects/diseases
• local availability
• proven ability to produce acceptable yields under local physical and management conditions (local adaptation)
• low cost
• ability to be multiplied successfully on the farm
• adapted to low soil fertility and management practices
• low responsiveness to increased soil fertility, use of fertilizer or other improved practices
These are produced (by crossing two or more inbred lines of a crop) by plant breeders at seed multiplication centers. Advantages:
• out-yield local varieties by up to 35 percent
• more resistant to insects/disease
• responsive to improved practices and fertilizer use.
• not locally available
• not replicable on the farm (hybrid seed reverts back to original characteristics if replanted, yields drop sharply)
• unfamiliar to local farmers
• require good management practices
• have a narrower range of adaptation to growing conditions
Synthetics are improved varieties developed from cross-polinate lines tested for their combining ability. Advantages: Same as hybrids above
• greater genetic variability (more adaptable) than hybrids
• less expensive than hybrids
• seed can be replanted if carefully selected
(Same as hybrids)
Varieties improved through mass selection
These occur through natural crossing between plant lines without tests of combining ability. Advantages:
• better response to fertility and improved practices than traditional varieties
• cheaper than synthetics or hybrids
• seed can be replanted
• less responsive than hybrids or synthetics
• product of more random process
By using the TOOLS indicated in this subchapter, farmers and extensionists can choose the type and specific kind of seed for use on local farms. Once the type and specific varieties of seed are chosen, it is important to make sure enough quality seed is available. If a hybrid seed is chosen, then providing adequate seed involves identifying a professional seed multiplication center which has the variety, procuring and then distributing the seed. If farmers select a synthetic or mass-selected variety, initial procurement from a seed multiplication center may be necessary. However, synthetics and massselected varieties, like traditional varieties, may be replanted and therefore replicated on the farm.
Seed multiplication on the farm involves several steps. First, the farmer and extensionist must be sure the variety they wish to multiply is not a hybrid. Second, the farmer should determine the amount of seed he wishes to produce for replanting and designate a portion of his yield for that purpose. Third, during harvest and the processing of the crop, special care should be taken to select and dry the seed to replant. (See "How To Select Home Grown Seed" in the TOOL section.) Four, seed should be stored carefully away from sources of moisture, insects and disease which can damage it. Finally, when selecting seed for use at planting time with farmers, conduct a germination test and/or a field test to make certain seed quality is good.
Ralph has been working with local rice farmers for six months. They have been experimenting since last year with new varieties which a previous extension agent had introduced. Some of the new varieties had yielded much more than the local varieties. Three in particular are of note. One variety yielded double previous yields. Two others exceeded local variety yield by significant amounts. The farmer (Jo) who used the highest yielding variety also used a recommended application of nitrogen fertilizer. Of the farmers who used the other new varieties, only one (Abdul) used fertilizer at all, below the recommended rate.
This year, Ralph does not provide fertilizer to farmers himself and the farmers do not buy any on their own. The farmers insist on using the same new varieties, however. Jo is astonished to find that the highest-yielding variety of last year yields less than most local varieties. Abdul, who used a different new variety with some fertilizer, found his yield to be almost as good as last year. Ralph concludes that Jo's variety is probably a hybrid geared to special fertilizer and management practices, and that Abdul's is a synthetic or mass-selected variety. Ralph verifies his conclusions with regional ag researchers. He then explains the difference in variety types and characteristics to the farmers and recommends Abdul's variety fertilizer and a locally adapted package of growing practices. The farmers agree to use Abdul's variety, to purchase seed from him, and to forego the purchase of other outside inputs. Ralph plans to help each farmer multiply his or her own seed during the year. He also plans to test all the varieties present in the area with the help of the local ag research station.
ANOTHER SITUATION IN WHICH SEED SELECTION IS IMPORTANT:
Chris and her counterpart Jina have been working with a group of women on kitchen gardens. The women are particularly interested in reducing the amount of inputs they must purchase with hard-won cash. The two extension workers are therefore trying to determine several things: which local vegetable varieties can be easily grown for seed; what germination rates can they expect from these varieties; what varieties will maintain their viability in successive propagations? With time Chris learns from her investigation that there are no lists of "recommended varieties" for the area in which she works. She realizes she must learn about the seed from local farmers/gardeners, and by personal experience or local testing. She comes to understand that this will be a long process which must precede any gardening project.
1. ICE manual M 13 Traditional Field Crops
2. ICE manual M 2 Small Farm Grain Storage
3. ICE reprint R 25 Intensive Vegetable Gardening for Profit and Self-Sufficiency
4. ICE reprint R 40 Rice Production
5. ICE packet P 4 Small Vegetable Gardens
6. Locally available manuals, booklets and pamphlets on seed propogation and crop production.