Constraints and opportunities of Pachyrhizus spp. introduction in the current farming systems in Central and Southern Benin.

Agricultural productivity in Benin is challenged by poverty, food and nutritional insecurity and decrease of soil fertility. To remedy these challenges and improve particularly food and nutritional status of populations, a new crop Pachyrhizus ahipa. (Yam Bean) is being introduced in Central and Southern Benin. The present survey aims to assess constraints and opportunities of Pachyrhizus ahipa. introduction in the Central and Southern Benin farming systems. Municipalities were chosen in the agro-ecological zones of this part of Benin on the basis of poverty level, food security and nutritional status of populations. They are Ouèssè, Dassa-zoumè, Djidja and Kétou in the agroecological zone V (biggest zone); Djakotomey in the agro-ecological zone VI; Toffo in the agroecological zone VII and finally Dangbo in the agro-ecological zone VIII. In each of these municipalities, one (01) representative village has been chosen using results of previous works. A Rapid Rural Appraisal on the farmers' perceptions was led in each sampled village. Content analysis identified main variables rural household produce mainly for self consumption and for sale. Main production constraints are soil deterioration, insufficient labor availability, lack of financial means and finally climatic risk. The ex ante analysis of the Pachyrhizus ahipa's introduction reveals the potential of this crop to fulfill many current constraints quoted up

Introgression of trypanotolerance genes.

This doctoral dissertation consists of 6 chapters: general introduction; Estimating recombination in an advanced intercross population of mice (paper submitted for publication); A model for population growth of laboratory animals subjected to marker-assisted introgression: how many animals do we need? (published in Heredity (1999) 82, 16-24); Strategies to optimize marker-assisted introgression of multiple unlinked QTL (quantitative trait loci) (published in Mammalian Genome (2000) 11, 145-150); Trypanotolerance QTL introgression in mice: experimental results; general discussion. It was shown how the size of a breeding experiment increases with the number and size of the QTL region to introgress. Biological factors to be considered when estimating the required size of an introgression experiment are also highlighted. The experiment in mice showed that QTL introgression is feasible and successful, and that the background genotype is an important factor to be considered when analysing the results of such an experiment. The general discussion focuses on the introgression of trypanotolerance genes in cattle with an emphasis on Sub-Saharan zones in Africa

Marker-assisted introgression of trypanotolerance QTL in mice

A marker-assisted introgression (MAI) experiment was conducted to use genetic markers to transfer each of the three trypanotolerance QTL from a donor mouse strain, C57BL/6, into a recipient mouse strain, A/J. We used a backcross strategy that consisted of selecting two lines, each carrying two of the donor QTL alleles through the backcross (BC) phase. At the fourth BC generation, single-carrier animals were selected for the production of homozygous animal in the intercross phase. The QTL regions (QTLR) were located on chromosomes MMU1, MMU5, and MMU17. Groups of mice with different genotypes and the parental lines were subjected to a challenge with Trypanosoma congolense. The results show that trypanotolerance QTL was successfully moved into the recipient background genotype, yielding a longer survival time. The mean estimated survival time was 57.9, 49.5, and 46.8 days for groups of mice carrying the donor QTL on MMU1, MMU5, and MMU17 on A/J background. The mean estimated survival time was 29.7 days for the susceptible A/J line and 68.8 days for the resistant C57BL/6 line. The estimated QTLR effects are close to 30% smaller than those in the original mapping population which was likely caused by the difference in the background on which the effects of QTLR are tested. This is the first report of successful marker-assisted introgression of QTL in animals. It is experimental proof of the use of genetic markers for marker-assisted introgression in animal breeding

Farmers’ perceptions on characteristics of cassava (Manihot esculenta Crantz) varieties used for chips production in rural areas in Benin, West Africa

A survey aimed at collecting information about cassava varieties/cultivars and farmers’ perceptions concerning cassava and chemical food safety was conducted in 10 villages located in two agroecological zones in Benin. A structured questionnaire to interview farmers was employed. Out of 100 farmers sampled, most of them relaying on chips as food and source of income were women. Overall, 40% of all farmers marketed chips locally. Tasting was the main technique use by farmers to discriminate cassava varieties including Kpaki Kpika, Kpaki Soan, Logo Guesse Kotorou and BEN 86052. The latter being introduced by research centres. Both bitter and sweet cassava were produced and the sweet varieties being used for chips production by farmers who do perceive bitter cassava as toxic crop. Our results call for more investigations in promoting gender oriented safety and hygiene/sanitation techniques