Produ��o de sementes de culturas alimentares na regi�o da SADC

Criado para tratar os temas que limitam o acesso de fazendeiros em pequena escala, na �frica sub-Saara, para que possuam recursos para obterem colheitas de sementes de qualidade, das quais eles dependem para a obten��o dos alimentos e � o seu pr�prio meio de vida. Esta cole��o de artigos descreve os princ�pios bem sucedidos para as experi�ncias em comunidades que possuem produ��es de sementes. Entre outras coisas, os textos analisar�o o sistema de produ��o normal de sementes e seus modelos, propor�o caminhos para criar esquemas bem sucedidos para as comunidades que produzam sementes, descrever�o as pr�ticas pr�prias da produ��o de sementes para cereais seletos, plantas vegetativamente propagadas e outras colheitas, e esquematizar�o as pr�ticas b�sicas de neg�cios para os produtores de sementes.Produ��o de sementes, prote��o dos alimentos, qualidade, propaga��o de plantas, colheitas, modelos, fazendeiros, alian�as, pequenas fazendas, administra��o de neg�cios, �frica do Sul, Crop Production/Industries, F03,

Identification of groundnut (Arachis hypogaea) SSR markers suitable for multiple resistance traits QTL mapping in African germplasm

AbstractBackgroundThis study aimed to identify and select informative Simple Sequence Repeat (SSR) markers that may be linked to resistance to important groundnut diseases such as Early Leaf Spot, Groundnut Rosette Disease, rust and aflatoxin contamination. To this end, 799 markers were screened across 16 farmer preferred and other cultivated African groundnut varieties that are routinely used in groundnut improvement, some with known resistance traits.ResultsThe SSR markers amplified 817 loci and were graded on a scale of 1 to 4 according to successful amplification and ease of scoring of amplified alleles. Of these, 376 markers exhibited Polymorphic Information Content (PIC) values ranging from 0.06 to 0.86, with 1476 alleles detected at an average of 3.7 alleles per locus. The remaining 423 markers were either monomorphic or did not work well. The best performing polymorphic markers were subsequently used to construct a dissimilarity matrix that indicated the relatedness of the varieties in order to aid selection of appropriately diverse parents for groundnut improvement. The closest related varieties were MGV5 and ICGV-SM 90704 and most distant were Chalimbana and 47–10. The mean dissimilarity value was 0.51, ranging from 0.34 to 0.66.DiscussionOf the 376 informative markers identified in this study, 139 (37%) have previously been mapped to the Arachis genome and can now be employed in Quantitative Trait Loci (QTL) mapping and the additional 237 markers identified can be used to improve the efficiency of introgression of resistance to multiple important biotic constraints into farmer-preferred varieties of Sub-Saharan Africa

Aflatoxin B1 levels in groundnut products from local markets in Zambia

In Zambia, groundnut products (milled groundnut powder, groundnut kernels) are mostly sold in under-regulated markets. Coupled with the lack of quality enforcement in such markets, consumers may be at risk to aflatoxin exposure. However, the level of aflatoxin contamination in these products is not known. Compared to groundnut kernels, milled groundnut powder obscures visual indicators of aflatoxin contamination in groundnuts such as moldiness, discoloration, insect damage or kernel damage. A survey was therefore conducted from 2012 to 2014, to estimate and compare aflatoxin levels in these products (n = 202), purchased from markets in important groundnut growing districts and in urban areas. Samples of whole groundnut kernels (n = 163) and milled groundnut powder (n = 39) were analysed for aflatoxin B1 (AFB1) by competitive enzyme-linked immunosorbent assay (cELISA). Results showed substantial AFB1 contamination levels in both types of groundnut products with maximum AFB1 levels of 11,100 μg/kg (groundnut kernels) and 3000 μg/kg (milled groundnut powder). However, paired t test analysis showed that AFB1 contamination levels in milled groundnut powder were not always significantly higher (P > 0.05) than those in groundnut kernels. Even for products from the same vendor, AFB1 levels were not consistently higher in milled groundnut powder than in whole groundnut kernels. This suggests that vendors do not systematically sort out whole groundnut kernels of visually poor quality for milling. However, the overall contamination levels of groundnut products with AFB1 were found to be alarmingly high in all years and locations. Therefore, solutions are needed to reduce aflatoxin levels in such under-regulated markets

Agronomic, genetic, and biochemical analysis of drought resistance in sorghum, and development of high yield potential sorghum hybrids for drought stress environments

Three different studies were performed using sorghum (Sorghum bicolor L. Moench) lines previously screened for field drought resistance in Sudan Africa, and other lines selected for superior agronomic performance from intercrosses among drought resistant lines. In two rainout shelter tests in which moisture was carefully controlled to induce pre-flowering and post-flowering stress treatments, and by use of appropriate checks, genotypes were classified on the basis of their reaction to the stress treatments relative to the checks. HD-1, a hybrid from Sudan, was found to be tolerant to pre-flowering stress, while CS3541, K886, and M35-1 were tolerant to post-flowering stress. Two lines P898012 and P954035, were found to possess good levels of resistance to both reactions. A diallel analysis was performed using four lines with contrasting drought reactions, namely P898012, M35-1, TX7000, and TX7078. It was found that the drought resistant lines had higher betaine/amino acid ratios, and higher proportions of proline, alanine, and gln + glu, governed mostly by additive gene action. Line M35-1 also had high levels of pipecolic acid, governed by non-additive gene action. A third study testing the combining ability of drought resistant lines was performed using 16 R-lines, 4 A-lines, and 3 checks. The A-lines had been previously selected for resistance to post-flowering drought stress. Most of the R lines were known to have pre-flowering stress tolerance. HD-1, RS610, and A623 x TX430 were used as checks. The 64 hybrids, 16 R-lines, 4 B-lines, and 3 checks were planted in three locations: Two dryland and irrigated locations at Lubbock, Texas, and one at the Purdue University Agronomy Farm near West Lafayette, Indiana. Two lines, 954035 and CS3541, performed consistently superior to the others in hybrid combinations in all locations. Significant general combining ability (GCA) and specific combining ability (SCA) effects were observed for all traits except saddle effect (taller plants at ends of rows) seed set and lodging, implying both additive and non-additive gene effects are important. Grain yield was significantly negatively correlated to all the morphological characters implying it is possible to select for yield under marginal rainfall areas by simply using the morphological traits. (Abstract shortened with permission of author.

Successful Community-Based Seed Production Strategies

Designed to address the issues that limit the access of small-scale farmers in sub-Saharan Africa to quality, affordable seed of the crops on which they depend for food security and livelihoods, this collection of articles describes successful principles for and experiences in community-based seed production. Among other things, the manuscripts analyze current seed production systems and models; propose ways to design successful community-based seed production schemes; describe proper seed production practices for selected cereals, vegetatively propagated plants, and other crops; and outline basic business practices for seed producers.Seed production, Food security, Quality, Plant propagation, Crops, Models, Farmers, Partnerships, Small farms, Business management, Africa, Crop Production/Industries, F03, E10,

Welfare Effects of Agricultural Technology adoption: the case of improved groundnut varieties in rural Malawi

This paper applies a program evaluation technique to assess the causal effect of the adoption of improved groundnut technologies on consumption expenditure and poverty measured by headcount, poverty gap and poverty severity indices. The paper is based on a cross-sectional farm household level data collected in 2008 from a sample of 594 households in rural Malawi. A sensitivity analysis is conducted to test the robustness of the propensity score based results using the rbounds test and the mean absolute standardized bias (MASB) between adopters and non-adopters. The analysis reveals robust and positive and significant impacts of improved groundnut variety adoption on per capita consumption expenditure and on poverty reduction. The findings generally provide justification for continued public and private investment in groundnut research and outreach in Malawi

Improving efficiency of knowledge and technology diffusion using community seed banks and farmer-to-farmer extension: experiences from Malawi

Background: Agri-innovations are mostly delivered to farmers through private and public sector-led institutions around the world, with various degrees of success in Malawi. These distribution systems, on the other hand, do not meet everyone’s production and productivity needs, particularly those of smallholder farmers. Alternative gap-flling systems are therefore required. Over the course of 7 years, we performed two studies in Malawi to assess the efciency of integrated farmer led agri-innovation delivery mechanisms, in order to advise programming and delivery improvements. The frst study looked at the impact of farmer-led technology delivery on agricultural output and productivity. It was split into two phases: learning (2010–2015) and scaling-out (2016–2019). The second study looked at how smallholder farmers changed their behaviour, after receiving instruction during the scaling-out phase. A farmer led social network, community seed banks, was used as the research platform. Results: The number of farmers who had access to improved seed increased by 35-fold from 2.4% in the baseline year. Groundnut, the major study crop, had a 1.8-fold increase in productivity. In sorghum, and common bean, the diference in grain yield between benefciaries and control populations was 19% and 30%, respectively. The lowest afatoxin contamination was found in groundnut grain samples from trained farmers, showing that learning had occurred, with three training sessions sufcient for initiating and sustaining adoption of agri-innovations. Conclusions: Many developing country economies have limited investments in agricultural extension and advisory services, and as well as inefcient agri-input delivery systems, limiting access to science solutions needed to boost productivity. The farmer-led technology and knowledge dissemination systems examined in this research, are appropriate for a variety farming contexts, especially for crops underinvested by private sector, and where public extension and advisory services are poorly funded