Feasibilty of zein proteins, simple sequence repeats and phenotypic traits for background selection in quality protein maize breeding

Widespread adoption of quality protein maize (QPM), especially among tropical farming systems has been slow mainly due to the slow process of generating varieties with acceptable kernel quality and adaptability to different agroecological contexts. A molecular based foreground selection system for opaque 2 (o2), the cause of enhanced lysine content in maize exists. Background selection systems albeit, are poorly developed in spite of the mapping of putative loci associated with kernel modification and knowledge on causes of modification. The aim of this study was to develop background selection systems for o2 introgression into locally adapted genotypes. Experiments were conducted at Makerere University Agricultural Research Institute, Kabanyolo (MUARIK), in Uganda on backcross progeny (BC1F1) and BC2F2), derived from a locally adapted line 136R and a QPM donor CML176. We tested the use of zein proteins known to influence modification as well as DNA markers and phenotypic descriptors as tools for background selection for recurrent parent genome and modifier loci in locally adapted maize genotypes. Simply inherited traits such as maize streak virus disease resistance were suitable for background selection. Other traits include plant and ear heights. The simple sequence repeats markers mapped to chromosomes 3, 5, 7, respectively and associated with quantitative trait loci (QTL) conditioning resistance in maize to grey leaf spot and anthesis to silking interval were suitable for assay of recurrent parent genome. The 27-kDa g zein protein levels was suitable for background selection for kernel modification. It should, however, be used along with other zeins such as the 22 kDa and 19 kDa zein proteins.L'adoption du ma\uefs de prot\ue9ne de qualit\ue9 (QPM), sp\ue9cialement parmi les syst\ue8mes culturaux tropicaux a \ue9t\ue9 lente principalement due au processus lent de g\ue9n\ue9ration de vari\ue9t\ue9s avec de grains acceptables de qualit\ue9 et d'adaptabilit\ue9 \ue0 diff\ue9rents contextes agro\ue9cologiques. Il existe une cause du contenu am\ue9lior\ue9 de la lysine dans le ma\uefs, un syst\ue8me bas\ue9 sur la s\ue9lection mol\ue9culaire opaque 2 (o2). Malgr\ue9 les syst\ue8mes de s\ue9lection de fond, ceux-ci sont pauvrement d\ue9velopp\ue9s en d\ue9pit du "mapping" du loci associ\ue9 avec la modification du grain et la connaissance sur les causes de modification. L'objet de cette \ue9tude \ue9tait de d\ue9velopper les syst\ue8mes de s\ue9lection de fond pour l'introgression o2 dans les g\ue9notypes localement adapt\ue9s. Des essais \ue9taient conduits sur la prog\ue9nie de "backcross" (BC1F1) et BC2F2), d\ue9riv\ue9s de lign\ue9es adapt\ue9es 136R et un QPM doneur CML176. Nous avons test\ue9 l'usage des prot\ue9ines z\ue9ines capables d'influencer de modifications des marqueurs d'ADN et descripteurs ph\ue9notypiques comme mat\ue9riel de s\ue9lection de fond pour parent de g\ue9nome recurrent et modifiant de loci dans les g\ue9notypes de ma\ubfs localement adapt\ue9s. Des traits simplement h\ue9rit\ue9s dont la r\ue9sistance \ue0 la maladie de virus de m\ue8che \ue9taient appropri\ue9s pour la s\ue9lection de fond. D'autres traits incluaient la hauteur de plants et la taille de l'\ue9pis. Les marqueurs SSR repr\ue9sent\ue9s sur les chromosomes 3,5,7, respectivement et associ\ue9s aux traits quantitatifs loci (QTL) conditionnant la r\ue9sistance dans le ma\ubfs \ue0 la maladie de t\ue2che grise de feuilles ansi que l'intervalle de l'anthesis jusqu'\ue0 la s\ue9cr\ue9tion du "silk" \ue9taient appropri\ue9s pour \ue9valuation du g\ue9nome parent recurrent. Les niveaux de prot\ue9ines z\ue9ines 27-kDa g \ue9taient appropri\ue9s pour la s\ue9lection de fond pour la modification de grains. Ceci pourra \ueatre utilis\ue9 \ue0 c\uf4t\ue9 d'autres z\ue9ines telles que les prot\ue9ines z\ue9ines 22 kDa et 19 kDa

'It is like a tomato stall where someone can pick what he likes': structure and practices of female sex work in Kampala, Uganda.

BACKGROUND: Effective interventions among female sex workers require a thorough knowledge of the context of local sex industries. We explore the organisation of female sex work in a low socio-economic setting in Kampala, Uganda. METHODS: We conducted a qualitative study with 101 participants selected from an epidemiological cohort of 1027 women at high risk of HIV in Kampala. Repeat in-depth life history and work practice interviews were conducted from March 2010 to June 2011. Context specific factors of female sex workers' day-to-day lives were captured. Reported themes were identified and categorised inductively. RESULTS: Of the 101 women, 58 were active self-identified sex workers operating in different locations within the area of study and nine had quit sex work. This paper focuses on these 67 women who gave information about their involvement in sex work. The majority had not gone beyond primary level of education and all had at least one child. Thirty one voluntarily disclosed that they were HIV-positive. Common sex work locations were streets/roadsides, bars and night clubs. Typically sex occurred in lodges near bars/night clubs, dark alleyways or car parking lots. Overall, women experienced sex work-related challenges at their work locations but these were more apparent in outdoor settings. These settings exposed women to violence, visibility to police, a stigmatising public as well as competition for clients, while bars provided some protection from these challenges. Older sex workers tended to prefer bars while the younger ones were mostly based on the streets. Alcohol consumption was a feature in all locations and women said it gave them courage and helped them to withstand the night chill. Condom use was determined by clients' willingness, a woman's level of sobriety or price offered. CONCLUSIONS: Sex work operates across a variety of locations in the study area in Kampala, with each presenting different strategies and challenges for those operating there. Risky practices are present in all locations although they are higher on the streets compared to other locations. Location specific interventions are required to address the complex challenges in sex work environments

The genome and population genomics of allopolyploid Coffea arabica reveal the diversification history of modern coffee cultivars.

Coffea arabica, an allotetraploid hybrid of Coffea eugenioides and Coffea canephora, is the source of approximately 60% of coffee products worldwide, and its cultivated accessions have undergone several population bottlenecks. We present chromosome-level assemblies of a di-haploid C. arabica accession and modern representatives of its diploid progenitors, C. eugenioides and C. canephora. The three species exhibit largely conserved genome structures between diploid parents and descendant subgenomes, with no obvious global subgenome dominance. We find evidence for a founding polyploidy event 350,000–610,000 years ago, followed by several pre-domestication bottlenecks, resulting in narrow genetic variation. A split between wild accessions and cultivar progenitors occurred ~30.5 thousand years ago, followed by a period of migration between the two populations. Analysis of modern varieties, including lines historically introgressed with C. canephora, highlights their breeding histories and loci that may contribute to pathogen resistance, laying the groundwork for future genomics-based breeding of C. arabica

Feasibilty of zein proteins, simple sequence repeats and phenotypic traits for background selection in quality protein maize breeding

Widespread adoption of quality protein maize (QPM), especially among tropical farming systems has been slow mainly due to the slow process of generating varieties with acceptable kernel quality and adaptability to different agroecological contexts. A molecular based foreground selection system for opaque 2 (o2), the cause of enhanced lysine content in maize exists. Background selection systems albeit, are poorly developed in spite of the mapping of putative loci associated with kernel modification and knowledge on causes of modification. The aim of this study was to develop background selection systems for o2 introgression into locally adapted genotypes. Experiment

Feasibilty of zein proteins, simple sequence repeats and phenotypic traits for background selection in quality protein maize breeding

Widespread adoption of quality protein maize (QPM), especially among tropical farming systems has been slow mainly due to the slow process of generating varieties with acceptable kernel quality and adaptability to different agroecological contexts. A molecular based foreground selection system for opaque 2 (o2), the cause of enhanced lysine content in maize exists. Background selection systems albeit, are poorly developed in spite of the mapping of putative loci associated with kernel modification and knowledge on causes of modification. The aim of this study was to develop background selection systems for o2 introgression into locally adapted genotypes. Experiments were conducted at Makerere University Agricultural Research Institute, Kabanyolo (MUARIK), in Uganda on backcross progeny (BC1F1) and BC2F2), derived from a locally adapted line 136R and a QPM donor CML176. We tested the use of zein proteins known to influence modification as well as DNA markers and phenotypic descriptors as tools for background selection for recurrent parent genome and modifier loci in locally adapted maize genotypes. Simply inherited traits such as maize streak virus disease resistance were suitable for background selection. Other traits include plant and ear heights. The simple sequence repeats markers mapped to chromosomes 3, 5, 7, respectively and associated with quantitative trait loci (QTL) conditioning resistance in maize to grey leaf spot and anthesis to silking interval were suitable for assay of recurrent parent genome. The 27-kDa g zein protein levels was suitable for background selection for kernel modification. It should, however, be used along with other zeins such as the 22 kDa and 19 kDa zein proteins.L'adoption du maïs de proténe de qualité (QPM), spécialement parmi les systèmes culturaux tropicaux a été lente principalement due au processus lent de génération de variétés avec de grains acceptables de qualité et d'adaptabilité à différents contextes agroécologiques. Il existe une cause du contenu amélioré de la lysine dans le maïs, un système basé sur la sélection moléculaire opaque 2 (o2). Malgré les systèmes de sélection de fond, ceux-ci sont pauvrement développés en dépit du "mapping" du loci associé avec la modification du grain et la connaissance sur les causes de modification. L'objet de cette étude était de développer les systèmes de sélection de fond pour l'introgression o2 dans les génotypes localement adaptés. Des essais étaient conduits sur la progénie de "backcross" (BC1F1) et BC2F2), dérivés de lignées adaptées 136R et un QPM doneur CML176. Nous avons testé l'usage des protéines zéines capables d'influencer de modifications des marqueurs d'ADN et descripteurs phénotypiques comme matériel de sélection de fond pour parent de génome recurrent et modifiant de loci dans les génotypes de ma¿s localement adaptés. Des traits simplement hérités dont la résistance à la maladie de virus de mèche étaient appropriés pour la sélection de fond. D'autres traits incluaient la hauteur de plants et la taille de l'épis. Les marqueurs SSR représentés sur les chromosomes 3,5,7, respectivement et associés aux traits quantitatifs loci (QTL) conditionnant la résistance dans le ma¿s à la maladie de tâche grise de feuilles ansi que l'intervalle de l'anthesis jusqu'à la sécrétion du "silk" étaient appropriés pour évaluation du génome parent recurrent. Les niveaux de protéines zéines 27-kDa g étaient appropriés pour la sélection de fond pour la modification de grains. Ceci pourra être utilisé à côté d'autres zéines telles que les protéines zéines 22 kDa et 19 kDa

Resource flows and nutrient balances for crop and animal production in smallholder farming systems in Eastern Uganda

Resource flow models are useful tools that assist farmers in analysing their soil fertility management strategies and in planning, experimenting and adapting ways to improve the use of scarce local resources. Resource flows and farm nutrient balance studies were carried out in eastern Uganda to ascertain the movement of organic resources and nutrients in and out of the farm system during a participatory learning and action research (PLAR) process. The resource flows were transformed into nutrient flows and partial nutrient balances were calculated using the Resource Kit computer package. Results of a farmers soil fertility management classification at the start of the PLAR intervention in 1999 revealed that 3% of the farmers were good soil fertility managers (class I), 10% were average soil fertility managers (class II) and 87% were poor soil fertility managers (class III). The results indicate that the net farm nutrient balances in kg ha?1 per season for all the nutrients [nitrogen (N), phosphorus (P), and potassium (K)] were negative for both the good and the poor soil fertility managers. Class 1 farm balances irrespective of the season, were however more negative than those of class 3 farms. For the long rains seasons (LR 2000, 2001 and 2002), the average net farm nutrient balances for N, P, and K for class I farms were ?5.0, ?0.6 and ?8.0 kg ha?1 year?1, while for the short rains seasons (SR 2000 and 2001), the nutrient balances were ?3.5, ?0.5 and ?6.0 kg ha?1 year?1, respectively. For the class III farms, the average net farm nutrient balances for N, P, and K in the long rain seasons (LR 2000, 2001 and 2002) were ?3.3, ?0.3 and ?4.0 kg ha?1 year?1 while for the short rains seasons (SR 2000 and 2001), the nutrient balances were ?3.5, 0.5 and ?5.0 kg ha?1 year?1, respectively. Soil management interventions for these small-scale farmers should aim at reversing nutrient depletion with a focus on profitable management of the crop production system, which is the major cause of nutrient depletion