Thuo M.,Wolaita Sodo University |
Bell A.A.,University of Connecticut |
Bravo-Ureta B.E.,University of Connecticut |
Bravo-Ureta B.E.,University of Talca |
And 6 more authors.
Agriculture and Human Values | Year: 2014
Social networks play a significant role in learning and thus in farmers' adoption of new agricultural technologies. This study examined the effects of social network factors on information acquisition and adoption of new seed varieties among groundnut farmers in Uganda and Kenya. The data were generated through face-to-face interviews from a random sample of 461 farmers, 232 in Uganda and 229 in Kenya. To assess these effects two alternative econometric models were used: a seemingly unrelated bivariate probit (SUBP) model and a recursive bivariate probit (RBP) model. The statistical evaluation of the SUBP shows that information acquisition and adoption decisions are interrelated while tests for the RBP do not support this latter model. Therefore, the analysis is based on the results obtained from the SUBP. These results reveal that social network factors, particularly weak ties with external support (e.g., researchers, extension agents, etc.), partially influence information acquisition, but do not influence adoption. In Uganda, external support, gender, farm size, and geographic location have an impact on information acquisition. In Kenya, external support and geographic location also have an impact on information acquisition. With regard to adoption, gender, household size, and geographic location play the most important roles for Ugandan farmers, while in Kenya information from external sources, education, and farm size affect adoption choice. The study provides insight on the importance of external weak ties in groundnut farming, and a need to understand regional differences along gender lines while developing agricultural strategies. This study further illustrates the importance of farmer participation in applied technology research and the impact of social interactions among farmers and external agents. © 2014 Springer Science+Business Media Dordrecht.
Horacek M.,AIT Austrian Institute of Technology |
Hansel-Hohl K.,AIT Austrian Institute of Technology |
Burg K.,AIT Austrian Institute of Technology |
Soja G.,National Semi Arid Resources Research Institute NaSARRI |
And 2 more authors.
PLoS ONE | Year: 2015
The indication of origin of sesame seeds and sesame oil is one of the important factors influencing its price, as it is produced in many regions worldwide and certain provenances are especially sought after. We joined stable carbon and hydrogen isotope analysis with DNA based molecular marker analysis to study their combined potential for the discrimination of different origins of sesame seeds. For the stable carbon and hydrogen isotope data a positive correlation between both isotope parameters was observed, indicating a dominant combined influence of climate and water availability. This enabled discrimination between sesame samples from tropical and subtropical/moderate climatic provenances. Carbon isotope values also showed differences between oil from black and white sesame seeds from identical locations, indicating higher water use efficiency of plants producing black seeds. DNA based markers gave independent evidence for geographic variation as well as provided information on the genetic relatedness of the investigated samples. Depending on the differences in ambient environmental conditions and in the genotypic fingerprint, a combination of both analytical methods is a very powerful tool to assess the declared geographic origin. To our knowledge this is the first paper on food authenticity combining the stable isotope analysis of bio-elements with DNA based markers and their combined statistical analysis. Copyright: © 2015 Horacek et al.
Wurschum T.,University of Hohenheim |
Anyanga W.O.,National Semi Arid Resources Research Institute NaSARRI |
Hahn V.,University of Hohenheim
Helia | Year: 2014
Sclerotinia sclerotiorum (Lib.) de Bary is a yield-limiting factor and the major disease of sunflower (Helianthus annuus L.) in the temperate regions of the world. In this study, we characterized resistance to S. sclerotiorum midstalk rot and morphological traits in a population derived from a cross between two Sclerotinia resistant lines. Phenotypic data for 114 F3:4 lines and the two parents, NDBLOSsel and K04, were obtained under artificial infection in field experiments which yielded moderate to high heritabilities. Our results suggest that S. sclerotiorum resistance is highly quantitative and that different genomic regions may mediate the resistance in different tissues of the plant. We found transgressive segregation for all three resistance traits suggesting that both resistant parents carried complementary QTL. In addition, we investigated the segregation of two known QTL for midstalk resistance and found that one of them also acts as a major QTL in this cross between two resistant lines. Collectively, our results suggest that a QTL stacking approach is a promising way to increase resistance to S. sclerotiorum in elite sunflower germplasm. © 2014, Würschum et al.
Orawu M.,National Semi Arid Resources Research Institute NaSARRI |
Melis R.,University of KwaZulu - Natal |
Laing M.,University of KwaZulu - Natal |
Derera J.,University of KwaZulu - Natal
Euphytica | Year: 2013
Cowpea aphid-borne mosaic virus (CABMV) is a major virus disease in Uganda that causes substantial loss of the cowpea crop especially in growth and yield. The mode of gene action conferring resistance to the virus is not well understood. The objective of the study was to determine the genetic inheritance of resistance in cowpea crosses. Three susceptible (S) cowpea landraces that are commonly grown by farmers were crossed with five introduced resistant cowpea varieties in accordance with a North Carolina mating design II scheme. The F1, F2 and BC1F1 progenies generated were evaluated in the field together with their parents. They were then infected with two infection methods namely: by spreader-rows of S cultivar (Ebelat) and artificial inoculation of virus extracts. The results obtained showed that general combining ability (GCA) and specific combining ability (SCA) effects were significant, indicating that both additive and non-additive gene effects controlled virus infection. The results further demonstrated that the GCA effects (59. 8 %) were more important than SCA effects (40. 2 %) in determining virus resistance in the cowpea varieties. Utilisation of good general combiners of the varieties MU-93, IT82D-516-2, SECOW-2W and IT85F-2841 in hybridisation to improve virus resistance in cowpea crosses would be recommended. The result of this study provided an indication that CABMV resistance was conditioned by more than one recessive gene in eight populations, but also revealed resistance to be conditioned by a single recessive gene in the other seven populations. Observation of continuous distribution of progenies for severity data in the F2 populations also confirmed significance of quantitative inheritance for CABMV resistance. Therefore, the significance of GCA effects suggests that recurrent selection could be applied to accumulate the additive genes for resistance in F2 populations. © 2012 The Author(s).
Sehr E.M.,AIT Austrian Institute of Technology |
Okello-Anyanga W.,Makerere University |
Okello-Anyanga W.,National Semi Arid Resources Research Institute NaSARRI |
Hasel-Hohl K.,AIT Austrian Institute of Technology |
And 8 more authors.
Journal of Crop Science and Biotechnology | Year: 2016
Sesame (Sesamum indicum L.) is one of the most important ancient oilseed crops grown throughout the tropical and subtropical regions of the world. In Uganda, most of the cultivated sesame varieties are local landraces which are frequently traded between farmers. Although these traditional landraces are an important source of genetic diversity, knowledge of their genetic diversity is still limited. Agromorphological traits and a set of published and newly developed microsatellite markers were analyzed on a collection of 121 accessions of Ugandan sesame landraces. CpSSR analysis revealed four haplotypes, whereby haplotype B was present in 96% of the individuals. The analysis of nSSR markers from 6 non-coding regions revealed a mean PIC value of 0.56 whereas the PIC value of eight selected EST-derived SSRs was 0.26. Accession-wise, the expected heterozygosity (He) varied from 0 to 0.396. AMOVA revealed that the majority of the variance occurred among the individuals accounting for 75% of the total variation, only 6% was attributed to differences among the districts, pointing towards a high gene flow (Nm = 4.476). These results are supported by the PCoA analysis as well as the NJ tree both of which revealed no clustering of the accessions according to their geographic origin. Also the statistical analysis of 10 agromorphological traits indicated no clear pattern related to the geographic origin. Such a poor grouping, indicative of considerable gene flow across geographic domains, could be explained either by a high outcrossing rate, and/or through extensive seed trading. © Korean Society of Crop Science and Springer 2016.
Upadhyaya H.D.,Indian International Crops Research Institute for the Semi Arid Tropics |
Sarma N.D.R.K.,Agricultural Research Station |
Ravishankar C.R.,Zonal Agricultural Research Station |
Albrecht T.,University of Hohenheim |
And 12 more authors.
Crop Science | Year: 2010
Finger millet [Eleusine coracana (L.) Gaertn.], among small millets, is the most important food crop in some parts of Asia and Africa. The grains are a rich source of protein, fiber, minerals, and vitamins. A core collection of 622 accessions was developed. The aim of this study was to develop a mini-core collection using multilocational evaluation data of the core collection. Six hundred and twenty-two accessions together with six controls (four common and two location-specific) were evaluated for 20 morphological descriptors at five agroecologically diverse locations in India during the 2008 rainy season. The experiment was conducted in α design with two replications at Patancheru and in augmented design with one of the six controls repeated after every nine-test entry at other locations. The hierarchical cluster analysis of data using phenotypic distances resulted in 40 clusters. From each cluster, ~10% or a minimum of 1 accession was selected to form a mini-core, which was comprised of 80 accessions. The comparison of means, variances, frequency distribution, Shannon-Weaver diversity index (H'), and phenotypic correlations revealed that the mini-core captured the entire diversity of the core collection. This mini-core collection is an ideal pool of diverse germplasm for identifying new sources of variation and enhancing the genetic potential of finger millet. © Crop Science Society of America.