Official Newsletter of the WANA Seed Network
No. 35, July 2008
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Short communications on practical research or relevant information on agriculture or seed technology are presented in this section.
Participatory 'Mother-Baby' Trials in Common Bean Breeding in Southern Ethiopia
Asrat Asfaw and Fistum Alemayehu*
*) Awassa Agricultural Research Center, South Agricultural Research Institute, P.O. Box 6, Awassa, Ethiopia
Introduction
Common bean (Phaseolus vulgaris L.) domesticated in Andean South and Middle America, is believed to have been introduced together with maize into the east coast of Africa by Portuguese and Spanish traders in the 16th and 17th century. However, according to some reports beans were introduced into Ethiopia as early as 1520 (Habtu, 1994) or later in the 16th century (Assefa, 1985). Since then farmers have developed ecotypes adapted to local conditions by conserving and exploiting useful alleles which have resulted into a wide range of morphologically diverse landraces. Moreover, under the national bean-breeding programs, new germplasm is continually added from different parts of the world.
In developing countries, nearly 80% of dry bean is produced by smallholder farms with endemic poverty. Beans are the most important food legume for direct human consumption in the world, and are a traditional staple in many parts of East Africa (Wortman et al., 1998). In Eastern and Southern Africa, beans are the second most important protein sources and the third most important caloric source after cassava and maize (Pachico, 1993). While traditionally a food security crop throughout the region, intra-regional trade of common beans is gaining in importance.
Ethiopia is among the top ten common bean producers in sub-Saharan Africa (Hillocks et al., 2006) where the crop occupies considerable area, providing food and cash for millions of farmers. At present, it is evolving as an important source of foreign currency for the country in general and cash income for smallholder farmers in particular (Asrat et al., 2007). Among pulses, common bean covered about 4.8% of export earnings in 2001. This makes the crop strategic in alleviating malnutrition and ensuring food security.
Common bean is mainly produced in the low to medium altitude areas (1000-2200masl) for both home consumption and local/export markets. Its production is very diverse in terms of agro-ecology and cropping system, often cultivated as sole or in association with other crops mainly with low external input where landraces and informal seed sources are predominant (Asrat et al., 2007). It is produced twice a year i.e. in 'Belg' (February to April) and 'Meher' (June to October) season depending on the rainfall pattern of the area. In the 'Belg' season, beans are intercropped with maize, sorghum and coffee while in the 'Meher' season, beans are often planted as sole or relay crop with maize, sorghum, etc. In central rift valley, 'Meher' is the main production season whereas in southern region, large share of production comes from 'Belg' season planting.
Why participatory mother-baby trials?
In the southern Ethiopia, production largely depends on farmer's varieties which are believed to be of narrow genetic base compared to other bean growing countries in Africa. Farmers' bean varieties that have passed through many generations of natural and human selection for end-use quality are found to be low yielding and susceptible to angular leaf spot, bacterial blight and bean fly.
The national conventional common bean breeding program has developed many productive varieties that perhaps can increase yield per unit area. However, in the southern region, there has been a very limited adoption of improved bean varieties by smallholder farmers, especially the women. This could be attributed to:
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Less targeting of farmers production environments: the selection environments in conventional bean breeding program are generally fertilized, well weeded, sole crop and the land is flat, mostly fertile and uniform. In contrary, the farmers' bean production environments in the region are mostly non-fertilized, sole/relay/inter cropping system, and the land is sloppy, less fertile and heterogeneous. There is a mismatch between the selection and farmers production environments. |
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Less effectiveness in addressing need of clients: since there is no participation of farmers and other stakeholders in the variety development process, most conventionally bred bean varieties are less acceptable because of non-attractive seed color, seed size, cooking time and taste and inadequate diversity to meet local preferences of bean farmers and consumers. |
The efficiency of bean breeding program can be improved by matching the selection environment with target farmers' environment and ensuring participation of farmers and end users in the breeding process. Farmer participation in the breeding process helps to fit the crop to specific needs and uses of farming communities (Ceccarelli et al., 2000), increases client orientation and gains in plant breeding efficiency (Witcombe et al., 2005), and improve cultivar adoption (Horne and Stur, 1997). Mother-baby trial is one of the techniques for integration of clients or end-users need and addressing actual production environment in the crop improvement process.
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Stages of breeding and mother-baby trials
Plant breeding usually comprises three stages, namely generating variability, fixation of created variability and testing of the fixed variation (Schnell, 1982). Witcombe et al., (2005) further elaborated additional breeding stages such as goal setting, seed supply and outcome assessment. Mother-baby trial is one of the techniques for participatory varietal evaluation (PVE) and best applicable at varietal evaluation/testing stage of the breeding process.
Different models in mother-baby trials
Different researchers are employing different mother-baby trial design models (Witcombe et al., 2005) as follows:
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Replicated mother trial (12 entries) and baby trial (4 entries) in an incomplete block lattice evaluated as practiced by CIMMYT and its national program partners on maize in South Africa (Banziger and Cooper, 2001; Witcombe et al., 2005) |
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Single replicate mother trial of about 60 entries in year one and baby trials in following year based on entries selected from mother trial practiced by West Africa Rice Development Association and its national program partners in rice trials (Gridley et al., 2002; Witcombe et al., 2005). |
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Single replicate mother trial under a single management regime (the farmer's own) and baby trials where usually each farmer grows only one test entry alongside his/her local control used by CAZ and its collaborating NGOs and GOs in Asia (Witcombe, 2002; Witcombe et al., 2005) |
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Replicated mother trials at communal plots and non-replicated baby trials based on farmers selection in individual farmer plot model practiced by SARI in common bean breeding in southern Ethiopia (Asrat et al., 2004). |
Methodological approach of mother-baby trial at SARI Experimental sites: The trials were conducted in two rural communities, Remeda and Korangoge near Awassa in Sidama zone of the South Regional State of Ethiopia from 1999 to 2003. Remeda (1900 masl) represents the tepid to cool moist and humid mid-highland whereas Korangoge (1600 masl) represents the hot to warm sub-moist lowland areas of bean production.
Research design: It involves participatory communal plot selection (mother trial) on station followed by on-farm performance and diffusion of selected materials (baby trials). Forty-four farmers, including 10 women and 34 men representing different user groups, selected from the two villages were participated in selection process.
In the first year (1999 belg season) the farmer selectors were invited to attempt selection from 147 diverse genotypes planted at Remeda on-station mother trial for sowing in their individual on-farm plots (baby trials) in succeeding years. All the lines retained by individual farmer selections from the baby trials per cropping season, were pooled and planted on communal plot of mother trial for group evaluation and selection. The selection was made at physiological maturity and grains of each line from previous year harvest were presented in transparent plastic bags at time of evaluation to give farmers options of selection for seed characteristics. The farmers used their own judgment based on their own selection criteria to retain or reject the materials without any interference from the researchers.
Results of mother-baby trials
The number of lines selected by a farmer ranged from five to 51 and on average, a farmer selected 15 lines at first selection cycle from mother trial in belg 1999. At the final section cycle in baby trials i.e., in 2002, the number of lines selected by a farmer ranged from one to four and on average, a farmer selected two lines. This indicated that the range and average number of lines selected by a farmer decreased from first to final selection. At the final selection, the 27 farmer-selectors from two villages retained 17 large and 17 small-medium seeded beans i.e., 34 lines from the original 147 diverse lines they were exposed to in 1999 mother trial.
The farmers retained large numbers of lines for production in the two villages. This is because farmers need diversity for different purposes in the villages: varieties performing well with (responsive) or without fertilizers, beans preferred in local market and/or home consumption (women), beans suitable for sole or intercropping, etc. These diverse user preferences are positive values contributing to on-farm conservation of bean genetic diversity. Participating farmers in breeding process created access for the communities to improved bean germplasm (new genes) and increased intra-varietal diversity on-farm and at the experimental sites where there has been low level of bean agro-biodiversity. Sperling et al (2001) stated that PPB has a biodiversity enhancement role as it gives the community a chance of getting wider access to germplasm, information/related knowledge, and targeting of more micro-niches.
Farmers applied diverse selection criteria for maintaining bean varieties on their own field. The presence of diverse selection criteria in the bean production system indicates the complexity of the user's need and production conditions (Table 1). The more diverse the selection criteria, the better a chance of maintaining large diversity on-farm as all positive traits of beans can't be found in a single variety. The selection process and subsequent interviews with farmers revealed that seed color and seed yield were the main criteria to retain or reject a line. This was followed by large seed size, tall plant height, early maturity, high pod load, long pod, high number of seed per pod (>5 seeds/pod), strong stem (non lodging), erect growth habit, pod clearance from the ground, good taste, fast cooking, etc being descriptor to select a good line.
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Positive criteria
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Negative criteria
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Table 1. Farmers' selection
criteria for common bean varieties
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A
farmer attempting single plant selection on segregating populations
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The on-farm performance of the lines on baby trials is presented in Table 2. The new farmer's selections with small and medium seed size were better than that of the local farmer variety. The best yielding new small and medium seed size selections on average gave 19 to 100% yield advantage over local farmer variety. This indicated that the new bean genotypes injected in the farmers' production system out performed the local farmer variety.
In 2001 and 2002, among the new farmer selections evaluated under different management, DICTA-109 in mother trial and AFR-702 in baby trial recorded the highest yield of 1566 and 1660 kg ha-1, respectively (Table 3). Table 3 also revealed that some of the better preferred variety like CAL-170 with mean preference rating of 3.9 yielded lower and the high yielding variety DICTA-109 rated with medium preference of 2.6. This indicated that for adoption of a new bean variety not only grain yield but also farmer's qualitative traits/assessments are vital. In general, the overall selection process with farmers in both mother and baby trials revealed that farmers are capable of selecting varieties that give superior yield in their own field. This is in line with Ceccarelli et al (2000) who stated that farmers can handle and select among a large number of segregating lines and it is possible to transfer the responsibility of selection to farmers in their field.
| Varieties |
Range
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Mean
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Korangoge
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Remeda
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Korangoge
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Remeda
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| LSB |
312-2440
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620-2350
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1353
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1344
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| SMB |
770-3230
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690-3240
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550
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1965
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| Local |
290-3109
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430-1920
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1837
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1072
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| LSB 1 |
630-3130
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880-3610
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18261
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1830
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| SMB1 |
240-3810
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920-3720
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2191
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2173
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| Average of LSB vs local2 |
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73.6
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125.4
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| Average of SMB vs local2 |
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96.8
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183.3
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| Best yielding LSB vs local2 |
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99.4
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170.7
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| Best yielding SMB vs local2 |
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119.3
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202.7
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| Note: LSB= large seed bean; SMB= small and medium seed
bean; 1 Best yielding line at each farmer field; 2Yield advantage (%) of farmers selection over local variety |
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| Table 2. Average grain yield (kg ha-1) and yield advantage of farmers selections (baby trial) over local variety in 2000 | ||||
| Variety |
Mean grain yield
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Mean preference rating 1
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Mother trial
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Baby trial
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CAL-170
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999
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728
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3.9
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AFR-697
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949
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1,086
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2.9
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AFR-702
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1,324
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1,660
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3.5
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AFR-708
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1,070
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809
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3.1
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DICTA-109
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1,566
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1,530
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2.6
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OBA-4
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1,113
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1,341
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3.2
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Roba-1
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1,415
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1,144
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3.6
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RAB-585
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1,201
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1,245
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3.8
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Red Wolayta (local)
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1,117
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839
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2.9
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| 1 Variety preference rating where 5 = most preferred and 1 = less preferred | |||
| Table 3. Mean grain yield (kg ha-1) and farmer preference of bean lines in mother and baby trials in 2001 and 2002 at two locations (average of two years and two locations) | |||
Participatory variety diffusion
The varieties that got wider acceptance were placed in participatory variety diffusion scheme similar to that for PVS and PPB through individual farmers and cooperative based initiatives. Two common bean varieties identified through mother-baby trials were included in the program: Ibado and Omo-95. With individual seed producer scheme, farmers were given initial seed of preferred varieties in revolving seed system in which a farmer receive initial seed of a variety on free and payback in kind the amount he/she received from the research at harvest time. In the process, research, university and respective area office of agriculture and rural development were involved. The research provided training on bean seed production and post handling to development agents and initial seeds of preferred varieties. The development agents in turn provided on-farm training to farmers. Research, development practitioners and farmers monitored the entire operation jointly.
At the harvest, those better managed fields that fulfilled minimum seed production requirements, purchased back by research for redistribution to other farmers in the area and sold as seed directly by producer farmers to NGOs operating at distant locations. For example, one farmer at Boricha produced 1600 kg of Ibado seed and from that 500 kg seed sold to NGO operating in another zone. Moreover, 3000 kg seed was collected in a revolving seed scheme for redistribution to other farmers for next cropping season. In Boditi, an NGO Inter-aid France provided initial seed of Ibado and Omo-95 varieties to farmers in revolving seed scheme, where it established a community seed bank for farmers to keep seed for next planting. The farmer who put seed in bank has access to seed credit, double the amount of seed he/she saved in the bank. With this scheme, nearly 5000 kg seed of two varieties saved in the seed bank in 2007 cropping season. This made seed easily available to farmers in their vicinities and quickly reach many farmers with new varieties.
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Field
day on cooperative based seed production scheme
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In cooperative based scheme, varieties with high market demand are targeted and farmers, research, NGOs, BoARD, farmer's unions (FU) and exporters were involved. Seed production was initiated along with market oriented bean production in order to supply seed to producers continuously. FU provides inputs (seeds and fertilizers) with down payment and collects seed back from seed growers for next season distribution. A joint task force from seed chain partners monitored seed production. Field days were organized on seed multiplication plots before harvesting (see photo) for farmers, researchers, development practitioners, seed processors, grain traders and policy makers for joint evaluation and scaling-up. Farmers involved in seed production are organized into seed producers' cooperatives through the support of an NGO, Self-help International. The present effort of organizing farmers into seed producers' union will be the first of its kind for the country.
Conclusion
Participating farmers in common bean breeding and variety diffusion process created access for the communities to diverse germplasm pool (segregating populations and fixed variation) and increased intra-varietal diversity at on-farm level in the community where there were low levels of bean biodiversity. During selection, farmers retained 34 new bean lines (17 each from large and small-medium seed size) for production that will meet the need of wide range of users and adaptable to several microenvironments from the original 147 lines exposed to them. Prior to research intervention, only three cultivars were grown in the area. Thereafter the average number of varieties retained for planting increased from two to four. Number of small and medium sized bean lines retained increased from two to three and that of large seed size beans increased from zero to three. Farmers retained large number of diverse lines in participatory selection as compared to formal breeding which at the end mostly recommend few varieties. In general, farmers need diversity for different purposes: varieties performing well in no or low fertilizer or responsive to fertilizer application; varieties with preference for home consumption (women), local market or both; varieties suitable for sole cropping or intercropping. These diverse user preferences are promoting on-farm conservation of bean genetic diversity. Sperling et al (2001) stated that PPB has biodiversity enhancement role as it gives the community a chance of getting wider access to germplasm, information/related knowledge, and targeting of more micro-niches.
In individual as well as group selection farmers retained large proportion of large seeded lines as compared to small and medium seeded types. This demonstrated farmers' preference for newly introduced as well as reintroduced large-seeded bean types than their previously well-acquainted small seeded bean varieties. Large seeded beans are liked for their food value (good taste and swelling ability while cooked). The farmers used to grow large seeded beans before but the large seeded farmer's variety was lost because of its low yield as farmers shifted to growing productive small seeded types. However, through PPB the large seeded beans were reintroduced in to the production system.
Involving farmers in bean breeding created good insight into farmers' selection criteria/perception and their weight. Farmers applied diverse selection criteria in maintaining and rejecting bean varieties on their own field. The existence of diverse selection criteria in the bean production system indicates the complexity of the user's need and production conditions.
Exposing farmers to bean diversity resulted in identifying new variations and reintroduction of lost diversities that are more attractive to the farmers. The new as well as the re-introduction of bean diversities provided farmers more reliable seed yield under marginal environments as the newly selected lines expressed better yield advantage over existing farmer's varieties. The cultivation of new bean types by farmers and its subsequent supply to local markets created niche market for new products. The red mottled varieties introduced through PPB creating new market niche being exported to northern Kenya.
Some farmer's selections are entering the local markets and creating new demand niches for red kidney, red speckled and generally for large seeded beans. The red kidney sells extremely fast in the local markets with a 'matter of hours' and farmers complain that they cannot get the seed. The creation of new niche market for new beans in the region is encouraging for the communities who developed the varieties. Because of good price in local market some farmers are started multiplying the new beans in larger areas. The newly developed varieties are more acceptable to other farmers and consumers partly because of their higher yield potential and good seed characteristics.
In general integration of participatory approach in bean breeding and variety diffusion resulted in increased on-farm diversity, improved farmers breeding skills, identified farmers' selection criteria and preferences and introduced positive interactions, reduced research cost in relation to impact gained (acceptable varieties identified faster; fewer research dead-ends, effective in targeting users need).
References
Assefa, I. 1985. Bean production in Ethiopia. In Proceedings of Regional Workshop on Potential Beans (P. vulgaris L.) in West Asia and North Africa, 21-23 May 1983, Aleppo, Syria. CIAT, Cali, Colombia.15-38 pp
Asfaw, A., Dauro, D., and Kimani, P.M. 2004. Decentralized participatory bean breeding in southern Ethiopia. Proceedings of the 11th conference of the Crop Sciences Society of Ethiopia, 26-28 April 2004. Addis Ababa, Ethiopia.
Asrat A. Almekinders, C., Degu, G. and Alemayehu, F. 2007. Bean seed flow and exchange networks in Southern Ethiopia. Seed Info. No 33. ICARDA
Banziger, M. and Cooper, M. 2001. Breeding for low-input conditions and consequences for participatory plant breeding: Examples from tropical maize and wheat. Euphytica 122:503-519.
Ceccarelli, S., Grando, S., Tutwiler, R., Baha, J., Martini, A.M., Salahieh, H., Goodchild, A. and Michael, M. 2000. A methodological study on participatory barely breeding. I. Selection Phase. Euphytica 111: 91-104.
Habtu, A. 1994. Epidemiology of bean rust in Ethiopia. PhD Thesis, Wageningen University, Wageningen, the Netherlands. 172 pp.
Gridley, H. E., Jones, M. P. and Wopereis-Pura, M. 2002. Development of new rice for Africa (NERICA) and participatory varietal selection. In: (Witcombe, J.R., Parr, L. B. and Atlin, G. N. eds) Breeding Rainfed Rice for Drought-prone Environments: Integrating Conventional and Participatory Plant Breeding in South and Southeast Asia. Bangor, UK and Manila, Philippines. 23-28 pp
Horne, P.M. and Stur, W.W. 1997. Current and future opportunities for introduced forages in smallholder farming systems of south-east Asia. Tropical Grasslands 31(4): 359- 363.
Pachico, D. 1993. The demand for bean technology. In: Henry, G. (ed) Trends in CIAT commodities. CIAT, Cali, Colombia. 60-73 pp
Schnell, F. W. 1982. A study of methods and categories of plant breeding. Zeitschrift f´´ ur Pflanzenzuchtung 89:1-18.
Sperling, L., Ashby, J.A., Smith, M.E., Weltzein, E. and McGuire, S. 2001. A framework for analyzing participatory plant breeding approaches and results. Euphytica 122: 439-450.
Witcombe, J. R. 2002. A mother and baby trial system. In: (Witcombe, J.R., Parr, L. B. and Atlin, G. N. eds) Breeding Rainfed Rice for Drought-prone Environments: Integrating Conventional and Participatory Plant Breeding in South and Southeast Asia. Bangor, UK and Manila, Philippines. 79-89 pp
Witcombe, J.R., Joshi, K.D., Gyawali, S., Musa, A.M., Johansen, C., Virk, D.S. and Sthapti, B.R. 2005. Participatory plant breeding is better described as highly client-oriented plant breeding. I. Four indicators of client-orientation in plant breeding. Experimental Agriculture 41:299-319.
Wortman C.S., Kirkby, R.A., Eledu, C.A. and D. Allen, J. 1998. Atlas of common bean (Phaseolus vulgaris L.) production in Africa. CIAT Publication No. 297. CIAT, Cali, Colombia.