Toward a Cost‐Effective Fingerprinting Methodology to Distinguish Maize Open‐Pollinated Varieties

Warburton, Marilyn L.; Setimela, P.S.; Franco, Jorge; Córdova, Hugo; Pixley, K.V.; Bänziger, Marianne; Dreisigacker, Susanne; Bedoya, Claudia; MacRobert, John

doi:10.2135/cropsci2009.02.0089

Cited by 34 publications

(42 citation statements)

References 10 publications

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“…The genetic differentiation between the two OPVs (F ST = 0.14) is in the higher end of the F ST values obtained in an analysis of differentiation between heterotic groups of inbred lines from eastern and southern Africa [50] and similar to the mean F ST between 10 OPVs from Zimbabwe [21]. Despite this differentiation, the PCA (Figure 2) shows that when considered in the context of a diverse panel of predominantly local maize varieties from across Africa, both Staha and TMV1 show affinity with East African varieties.…”

Section: Discussionmentioning

confidence: 99%

Modern maize varieties going local in the semi-arid zone in Tanzania

et al. 2014

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BackgroundMaize is the most produced crop in Sub-Saharan Africa, but yields are low and climate change is projected to further constrain smallholder production. The current efforts to breed and disseminate new high yielding and climate ready maize varieties are implemented through the formal seed system; the chain of public and private sector activities and institutions that produce and release certified seeds. These efforts are taking place in contexts currently dominated by informal seed systems; local and informal seed management and exchange channels with a long history of adapting crops to local conditions. We here present a case study of the genetic effects of both formal and informal seed management from the semi-arid zone in Tanzania.ResultsTwo open pollinated varieties (OPVs), Staha and TMV1, first released by the formal seed system in the 1980s are cultivated on two-thirds of the maize fields among the surveyed households. Farmer-recycling of improved varieties and seed selection are common on-farm seed management practices. Drought tolerance and high yield are the most important characteristics reported as reason for cultivating the current varieties as well as the most important criteria for farmers’ seed selection. Bayesian cluster analysis, PCA and FST analyses based on 131 SNPs clearly distinguish between the two OPVs, and despite considerable heterogeneity between and within seed lots, there is insignificant differentiation between breeder’s seeds and commercial seeds in both OPVs. Genetic separation increases as the formal system varieties enter the informal system and both hybridization with unrelated varieties and directional selection probably play a role in the differentiation. Using a Bayesian association approach we identify three loci putatively under selection in the informal seed system.ConclusionsOur results suggest that the formal seed system in the study area distributes seed lots that are true to type. We suggest that hybridization and directional selection differentiate farmer recycled seed lots from the original varieties and potentially lead to beneficial creolization. Access to drought tolerant OPVs in combination with farmer seed selection is likely to enhance seed system security and farmers’ adaptive capacity in the face of climate change.

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Section: Discussionmentioning

confidence: 99%

Modern maize varieties going local in the semi-arid zone in Tanzania

et al. 2014

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“…The choice of this number was based on the studies of Warburton et al (2010) and Wasala and Prasanna (2013). The total number of individuals to be analyzed was 525.…”

Section: Extraction Of Genomic Dnamentioning

confidence: 99%

Genetic diversity and population structure of maize landraces from Cte dIvoire

Annicet¹,

Akanvou²,

Desire³

et al. 2016

Afr. J. Biotechnol.

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Maize (Zea mays L.) occupies an important place among food crops in Côte d'Ivoire. However, no study on the genetic diversity of the species has been performed to date. This study aims at analyzing the diversity and genetic structure of 35 maize accessions using 10 microsatellite markers. These accessions are from different agro-ecological zones representative of the Ivorian territory. The results showed that for all accessions studied, 47 alleles were detected, with an average of 6.71 ± 2.21 alleles per locus. The percentage of polymorphic loci and total genetic diversity, were 91.34% and 0.524 ± 0.159. A slight excess of heterozygotes was observed in the accessions (4.6%). The molecular analysis of variance showed that the total genetic diversity is mainly due to the intra-accession diversity (85.17%). The inter-accession diversity rate was estimated at 14.87%, which is in favor of moderate differentiation between the accessions. The Bayesian analysis grouped the accessions into two populations, regardless of geographical origin. These results provide basic information potentially useful in selection. The cross between two individuals from different groups might help exploit the phenomenon of heterosis.

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“…Considering the reproductive system of sorghum and the fact that sorghum landraces vary greatly in their mating system within a single year (Barnaud et al, 2008), it is not surprising that the integrity of improved varieties cultivated under village conditions in non-isolated fields (less than 100 m distance) can be quickly compromised (Rabbi et al, 2010;Warburton et al, 2010). Apart from W 1 , Soumba fields for food grain production are not spatially isolated from other sorghum varieties in Magnambougou.…”

Section: Varietal Integrity and Gene Flowmentioning

confidence: 99%

“…These efforts have taken various forms, including productionmarketing projects, promotion of technology packages, government programs and seed relief programs, as elucidated by Kaboré et al (2010); Baquedano et al (2010); Warburton et al (2010). Unfortunately, in most African countries sustainable seed provision for improved varieties is often hindered by the complex steps and regulations required for producing and commercializing seed (Guéi et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Farmers' seed selection and management can especially influence the genetic composition of the variety in open-pollinated crops such as pearl millet and maize (Morris et al, 1999;vom Brocke et al, 2003;Warburton et al, 2010;Lakis et al, 2011;Westengen et al, 2014). Using SNP markers, Westengen et al (2014) recently showed that the formal system seed of improved open pollinated maize varieties differentiated significantly from farmer recycled seeds of the same varieties in Tanzania.…”

Section: Introductionmentioning

confidence: 99%

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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

Deu¹,

Weltzien²,

Calatayud³

et al. 2014

Field Crops Research

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A B S T R A C TIn 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. Farmers were 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.

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Toward a Cost‐Effective Fingerprinting Methodology to Distinguish Maize Open‐Pollinated Varieties

Cited by 34 publications

References 10 publications

Modern maize varieties going local in the semi-arid zone in Tanzania

Modern maize varieties going local in the semi-arid zone in Tanzania

Genetic diversity and population structure of maize landraces from Cte dIvoire

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

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