SEED MULTIPLICATION OF IMPROVED, OPENPOLLINATED VARIETIES
Preface
These technical guidelines explain some of the methods that can be used in seed multiplication. The guidelines may be used by a community group, private company or secondary processor. Steps and options for communitybased seed multiplication techniques required are outlined. These guidelines are a result of various scientific experiments and experiences with communities in semi arid areas of Matabeleland South Province. Lessons from this province resulted in the production of these technical guidelines - to enhance the capacity of smallholder farmers and service support institutions in semi arid areas to strengthen sustainable community - based seed selection, production and multiplication. These technical guidelines are therefore aimed at offering a practical set of tools in strengthening the technical capacity of both practicing farmers and field facilitators working with grassroots people in participatory technology development, mostly focusing on seed resources development for improved food and livelihoods security. Knowledge gained from the guidelines should foster mutual learning by participants who are also expected to draw on their own practical experiences. Also, knowledge and skills gained from this guide should put farmers and development work facilitators in a way that challenges and influences the design, implementation, monitoring and evaluation of future development programmes at different levels for the benefit of all. The technical guidelines were developed and produced through wide consultations with partners and stakeholders involved in Practical Action Southern Africa's project on Enhancing Food and Livelihoods Security of Vulnerable Communities in Drought prone Areas of Zimbabwe being implemented in Gwanda, Matobo, Bulilima and Mangwe Districts of Matebeleland South Province. Practical Action Southern Africa hopes that these technical guidelines will become a useful resource fro smallholder farmers and development workers involved in community-based seed multiplication schemes in the region.
Introduction and background
Sub-Saharan African continues to suffer from food deficits and poverty largely due to lack of adequate agricultural inputs, among other constraints. In Zimbabwe, nearly 70 per cent of the population lives in rural areas and is highly dependant on agriculture for survival. Most of the communal farmers have abandoned traditional crop varieties in favour of improved hybrids. The demend for hybrid seed in communal areas had grown to an extent that 80 per cent of hybrid maize seed, for example, was being bought by this sector in any given season by 1994. Howeever the hyper inflationary environment experienced in Zimbabwe since tehe late 90s has resulted in seed and fertiliser prices escalating beyond the reach of most smallholder farmers, causing a decline in maize produced by this sector.
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Seed multiplication of improved open-pollinated varieties
Practical Action
To restore food security amoung smallholder farmers, stakeholders have been calling for the implementation of sustainable agricultural practices. Open-Pollinated Varieties (OPVs) are an option for achieving sustainability. Most OPVs are said to perfom well under low external input. To date, several organisations have been participating in promoting and advocating for the production and uti I isation of OPVs amoung small holder farmers. Crop production in Matebeleland South Province is mostly rain-fed. But, the province receives less than 600mm of rainfall per annum, which usually results in successive droughts and crop failures. The few seed stocks and gra i n reserves are wi ped out before the onset of the next farm i ng season. Community-based seed multiplication of OPVs can mitigate against hybrid seed unavailability and its soaring cost thereby increasing access to standard seed for communal areas, especially in drought prone areas.
Types of seeds
Standard grade seed: is seed that has not been produced under the certification scheme but meeting purity and germination test standards e.g. Retained seed. Certified Seed: is grown under the seed certification scheme e.g. hybrid
Activities in open pollinated varieties (OPVs) seed multiplication
Field crop inspections Done at least four times • Before planting • When crop is still young and growing in the field • When crop is flowering, and; • When crop is producing seed Before planting: To check on crops grown in the previous year. When the crop is growing: To check on isolation distances, weeds and removal of off types. At flowering: To check for weeds, diseases and how crop is being managed. Before harvesting: To make sure that all off types have been removed.
Requirements for seed multiplication
Land requirements; A seed crop should not be grown on a field that was grown on the previous year so as to: • • • • • Reduce pests and diseases Reduce weed pressure Improve soi I structure Ensure that seeds of previous crop wiII not germinate and mix with your variety and; Use of residual nutrients
Isolation This is the distance that should be left between similar seed crops to prevent cross pollination. The OPV seed production fields may be isolated in space or time, or both. The isolation distance for OPV seed production is normally 250 - 350 m.
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Seed multiplication of improved open-pollinated varieties
Practical Action
Planted first
(b) by space
Maize field (OPV) Planted 30 days or more later Commercial crop
(a) By time
Isolation by time and space of an OPV maize seed field
Bush fallow/other crops
Adapted from" Strategies for Strengthening and Scaling Up Community-Based Seed Production (CIMMYT), 2006. Isolation by time requires a planting interval (difference in sowing time) of 4 to 6 weeks to ensure that there is no pollen contamination of seed plots by other maize fields. The number of days to tasseling and silking of the seed field and neighbouring fields helps to determine the proper time isolation. If farmers cannot isolate by time or distance, they may harvest from the middle of their fields to minimise contamination, and the field should be at least about one hectare. Field Management for Seed Multiplication of Open Pollinated Varieties (OPVs) Planting • Grow seed of chosen variety alone (sole crop) to allow proper management Plant clean, viable seed • Get support from extension staff, trained farmers or crop guidelines so as to: • Plant using the correct spacing Use the correct seed fertiliser rates • Plant in rows for easy weed control and removal of off type plants Learn of the appropriate planting periods (use of seasonal calendar). Weeding (why we should weed) • Weeds reduce yield • Weeds reduce crop quality • Weed within four weeks after planting Inspect for pests and diseases • Thereafter, weeding depends on weed growth Weeding can be done mechanically using hoes, cultivators hand picking or chemically using herbicides. Rouging • Is the removal of off type plants • Off types are plants that do not resemble the variety grown Rouging is meant to have pure seed • Remove plant tha look different from the variety, e.g. plant height, leaf shape, leaf colour, flower colour • Rouge at least three times.
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Seed multiplication of improved open-pollinated varieties
Practical Action
How to multiply open pollinated varieties (OPVs)
• • • • • • • •
Buy recommended certified OPVs for your area. Grow OPVs in your poorer fields where you expect to harvest less than 15 bags per acre. The seed produced can be recycled for one or two reasons without any significant decline in vigour. Maintan purity of your seed and remember, in maize the tassel is the male flower that produces pollen and the si Iks constitute the female flower. Plant your OPVs for seed multiplication 200 - 300m away from other maize crops to avoid contamination. Inspect your crops before flowering and remove any plants that look different from others to keep your seed pure. When harvesting, take the ears of crops from the centre of the field for seed where there are least chances of cross poll ination from other crops. Keep your seed separate from other grain and protect it from storage pests. Commercially available varieties :ZM421, ZM521, ZM561, Matuba, KEP, Obantanpa
Open-pollinated varieties (OPVs) Open pollinated varieties are known sources of pollinated plants. Some have been improved and have variety names. The grain of an OPV may be saved for replanting if it is isolated from other maize varieties, or harvested from the middle of the field. The recycled seed will grow and yield as well as the original plants. Compared to hybrids, OPVs are less uniform ( and usually lower- yielding than hybrids in optimal environments). OPVs, however, have the advantage of being more stable than hybrids in low - yielding or stress environments. Farmers' checklist on when to grow a hybrid or OPV. When to grow a hybrid The farmer expects to harvest more than 2 tonnes /ha (15 bags per acre) of maize grain The cost of hybrid seed will be recovered from its yield. The farmer is located in a high potential environment and can afford inputs such as fertiliser and pesticides Hybrids adapted/suitable for local conditions are available. The farmer can obtain seed for timely planting When to grow an OPV The farmer expects to harvest more than 2 tonnes /ha (15 bags per acre) of maize grain The cost of hybrid seed may not be paid for by the farmer The farmer is located in a low potential environment and cannot afford extrs inputs. Not locally adapted / suitable hybrids are available The farmer cannot readily obtain seed
Adapted from" Strategies for Strengthening and Scaling Up Community-Based Seed Production (CIMMYT), 2006. Open-Pollinated Varieties seed production Farmers who are far from seed retail shops can benefit from growing maize OPVs, as the grain they harvest may be replanted as seed without significant yield loss. OPV seed may be recycled for a maximum of three seasons without significant yield loss. The longer a farmer recycles OPV seed, the greater the risk of contamination by pollen from neighbouring fields, and the deterioration of the variety. Seed production of OPVs is simpler than that of hybrids, because only one variety is planted and there is no need for detasseling. Nevertheless, maintenance of the OPV and production of the foundation seed of OPVs requires some special procedures, similar to hybrid seed production.
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Seed multiplication of improved open-pollinated varieties
Practical Action
Certified OPV seed
Farmers field Production
Grain for food, feed and sale
Shell, dry and then store the seed under appropriate conditions
Select good cobs for seed from the middle of your field
YOU MAY RECYCLE AN OPV FOR 1 - 3 SEASONS BEFORE BUYING NEW CERTIFIED SEED How to harvest, dry, shell and store seed At least 500 cobs should be harvested to ensure that the OPV maintains its own distinct variability. It it recommended that farmers harvest their ears at grain moisture content of about 1620% (i.e, once the husks are dry) and sun dry to about 14 percent moisture content before shelling for uniformity and quality (i.e, pest and disease-free not discoloured) and spread out in the sun for drying. In most areas, farmers may sun-dry their seed to the desired, moisture content. When syn-drying, ensure that the seeds are turned frequently to prevent "sun-burn" damage to the embryo. Most farmers sun dry their maize seed on a concrete slab, but if this is not available, the seed may be spread out on black plastic sheeting. Shelling may begin once the grain has reached moisture content of 14%. Farmers can apply the simple test to check whether the seed has reached 14% moisture content. Shell a cob and mix about 100 kernels with one gram of salt; if the salt feels moist after five minutes, then the cob needs to be dried further, but if the salt remains dry, then the shelling can begin. Shelling by hand minimises seed damage, but if a mechanical sheller is used, lower the settings (speed and severity of the threshing action). The shelled seed may then be cleaned (winnowed), and any chipped or diseased seeds are removed by hand. The seed is then treated with insecticides and fungicides against storage pests and fungi. When treating pesticides, observe safety recommendations and ensure that the seed is uniformly treated. Treated seed must never be used as food for animals or humans. Conditions necessary for seed storage It is important to know that seed is living and should be handled with care • Healthy viable seed has about 10% water. • Seed that is not dried well wiII rot whist in storage and will not germinate when planted
Good healthy seed
Small and shrivelled seed
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