169 research outputs found
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Evaluating Farmers' Pearl Millet Cultivars: Results from a Workshop on Farmer Participation in Breeding and Conservation of Genetic Resources
The objectives of the workshop were to describe the effects of farmers' own seed management practices on pearl millet [Pennisetum glaucum (L) R. Br.] populations and to identify possible implications for breeding and conservation of genetic diversity in this crop. Farmer cultivars were compared with selected improved varieties that had similar characters or were being used in the region
Revue et tendances pour la recherche en sélection participative en Afrique de l’Ouest
During the past 7-10 years experiments with participatory breeding in West-Africa have diversified considerably. Initially, most programs were focused on involving farmers in evaluating finished varieties, often already released, but not diffused. Based on these largely positive experiences, breeding programs have started to experiment with participatory approaches in the other stages of a plant breeding program as well. Most of these programs have not reached a stage where genetic gains can be evaluated. In most cases indications are strong that gains from farmers’ mass selection are at least similar to those of breeders. Thus the success of participatory plant breeding programs depends largely on appropriate divisions of tasks and responsibilities between producers and researchers according to everyone’s comparative advantage. In addition to achieving genetic gains in new farmer-preferred varieties, participatory breeding programs tend to address a range of other diverse goals, such as strengthening farmers’ capacities, conserving biodiversity or addressing poverty-related issues directly. The review shows that participatory selection programs have the capacity to address this multitude of goals while creating varietal improvements
Farmers’ seed systems and management practices determine pearl millet genetic diversity patterns in semiarid regions of India
Pearl millet [Pennisetum glaucum (L.) R. Br.] landraces provide nutritional quality and security under the harsh environmental conditions of Rajasthan, India. Using amplified fragment length polymorphism (AFLP), this study investigated pearl millet genetic diversity patterns and related the results to farmers' local knowledge and seed systems. Thirty-nine cultivars were assessed: 14 farmer landraces from western Rajasthan, 13 farmer landraces from eastern Rajasthan, and 12 control cultivars. Shannons' information index for western (H = 0.34) and eastern (H = 0.32) Rajasthan landraces was up to 14% higher than in composite-based improved cultivars. Analysis of molecular variance (AMOVA) revealed that variation within landrace populations was much higher than between regional samples. In the west, intra-village variation was higher than inter-village variation. In the east, variation between landrace groups bearing a specific name was higher than intra-group variation. Gene flow, inferred from genetic distances between populations, was used as an indicator for seed exchange between farmers. In western Rajasthan, seed exchange appears to be especially dynamic, as gene flow was greater than N,m = 25 among most of its populations. Farmers' knowledge of local cultivars and seed systems was, for the most part, supported by the AFLP analysis. These results are relevant for in situ maintenance and breeding strategies with a view to improving traditional cultivars, specifically performance and yielding stability
Effects of farmers' seed management on performance and adaptation of pearl millet in Rajasthan, India
Pearl millet (Pennisetum glaucum [L.] R.Br.) is the staple food and fodder crop of farmers in the semi-arid areas of north-west India. The majority of farmers in western Rajasthan depend on their own seed production and employ different seed production strategies that involve different levels of modern-variety introgression into landraces as well as different selection methods. This study quantifies the effects of three seed management strategies on environmental adaptation and trait performance. Forty-eight entries representing farmers' grain stocks - pure landraces or landraces with introgressed germplasm from modern varieties - as well as 33 modern varieties, multiplied by breeders or farmers, were evaluated in field trials at three different locations over two years under varying drought-stress conditions. Results indicate that the plant characteristics employed by farmers in describing adaptive value and productivity is an effective approach in discriminating the type of millet adapted to stress and non-stress conditions. It was also found that introgression of modern varieties (MVs) leads to populations with a broader adaptation ability in comparison to pure landraces or MVs alone - but only if MV introgression is practised regularly and is combined with mass panicle selection. Under high-rainfall conditions, farmer grain stocks with MV introgression show similar productivity levels as modern varieties. Under lessening rainfall, pure landraces show, in tendency, higher grain yields. In conclusion, farmers' seed management could form an integral part of participatory breeding programs
Farmers' seed management practices open up new base populations for pearl millet breeding in a semi-arid zone of India
Farmers in western Rajasthan (northwest India) produce and maintain their landrace populations of pearl millet through their own distinct seed management practices. The objective of this study was to characterize morphological and agronomic variability of different traits between and within three farmers' populations using quantitative genetic parameters. Populations examined were a typical landrace and two modified landraces, which were generated through farmer introgression of modern cultivars with different levels of subsequent selection. From these three populations, 100 random full-sib progenies were evaluated in field trials at two locations in western Rajasthan (Mandor and Jodhpur) over two years (1998 and 1999). Significant genetic variation existed within the three populations. Estimates of heritability were moderate to high for all observed traits. Predicted selection response for grain yield across environments was 1.6% for the typical landrace and 2.2% for both the modified landraces. Results suggest that the introgression of modern cultivars into landraces had increased the genetic diversity. Therefore, farmers' current breeding activities could open up new resources for plant breeding programmes aiming at plant improvement for the semi-arid zones of India
How an improved sorghum variety evolves in a traditional seed system in Mali: Effects of farmers’ practices on the maintenance of phenotype and genetic composition
In Africa, it is mostly the informal seed system that ensures farmers’ seed supply. This is partly because
the formal seed systems are not always effective in meeting demand for new seed varieties. Sometimes
informal seed recycling and exchange of improved sorghum varieties will take place alongside formal
initiatives, as is the case in southern Mali. Focusing on one particular village in the Dioïla district, we
analyze the efficacy of farmers’ strategies for preserving varietal seed purity and genetic integrity of an
improved inbred-line (Soumba variety). Six seed lots of Soumba, recycled for two to six years by farmers
using different practices, were collected and assessed in on-station trials in order to compare their
agronomic performance and phenotypic purity (off-type plant frequencies) with control versions of the
variety. Additionally, 30 panicle samples were randomly collected from five farmer fields sown with
recycled Soumba and assessed for phenotypic purity in a progeny nursery and investigated for molecular
diversity using 12 SSR markers. A total of 150 panicles from five other non-Soumba varieties were
collected in the village in order to investigate eventual gene flow and its potential genetic consequences
for the Soumba variety. In fields sown with recycled Soumba seed, between 2% and 14% of plants showed
phenotypic deviations from the typical Soumba variety. The progeny nursery and SSR marker analysis
verified the presence of the off-type plants observed in the field. The STRUCTURE program revealed
admixtures with other varieties in 23% of Soumba plants, confirming the presence of gene flow. Gene
diversity values in Soumba samples ranged from 0.006 for the commercial sample to 0.257 for recycled
samples. Introgression and contamination were best minimized when (1) farmers had received specific
training in seed production, (2) they could take advantage of isolated fields and (3) they could practise
true-to-type panicle selection. Farmerswere generally able to maintain the phenotype, as well as sustain
or even improve yield performance of their Soumba variety while at the same time genetically enriching
their seed stock
Characterization of semi-arid Chadian sweet sorghum accessions as potential sources for sugar and ethanol production
Sweet sorghum (Sorghum bicolor (L.) Moench) is an important crop in Chad that plays an economic role
in the countryside were stalks are produced mainly for human consumption without any processing.
Unfortunately, very little information exists on its genetic diversity and brix content. Studies
performed in 2014 and 2015 showed that there were significant variations (p < 0.001) for all assessed
quantitative traits. Potential grain yield (0.12–1.67 t ha−1), days to 50% flowering (68.3–126.3 days),
and plant height (128.9–298.3 cm) were among traits that exhibited broader variability. Brix content
range from 5.5 to 16.7% across accessions, was positively correlated to stalk diameter and plant
height, but negatively correlated to moisture content in fresh stalk and potential grain yield. Fresh
stalk yield range from 16.8 to 115.7 Mg ha−1, with a mean value of 58.3 Mg ha−1 across accession.
Moisture content in fresh stalk range from 33.7 to 74.4% but was negatively correlated to fresh
stalk yield. Potential sugar yield range from 0.5 to 5.3 Mg ha−1 across accession with an average of
2.2 Mg ha−1. Theoretical ethanol yield range from 279.5 to 3,101.2 L ha−1 across accession with an
average of 1,266.3 L ha−1 which is significantly higher than values reported under similar semiarid
conditions. Overall, grain yields were comparatively low. However, two accessions had grain yield of
more than 1.5 t ha−1; which is greater than the average 1.0 t ha−1 for local grain sorghum varieties in
Chad. These could have multi-purpose uses; grains, sugar and bioenergy production
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