Assessment of Rice Inbred Lines and Hybrids under Low Fertilizer Levels in Senegal

This research was conducted at the Africa Rice Sahel Regional Station (near Saint Louis, Senegal) during two wet seasons (i.e., July to November) in 2010 and 2011 with the aim of assessing the performances of introduced hybrid cultivars along with an inbred check cultivar under low input fertilizer levels. The five treatments used in this study were (a) the control (without any fertilizer application), (b) 37.5-4.4-8.3 kg N-P-K ha(-1), (c) half of recommend application in Senegal (75-8.75-16.5 kg N-P-K ha(-1)), (d) 112.5-13.3-24.8 kg N-P-K ha(-1), and (e) the recommended application in the country (150-17.5-33 kg N-P-K ha(-1)). There were significant year and cultivar effects for all traits. The fertilizer levels affected significantly most traits except panicle length and 1000-grain weight. The year x fertilizer level and year x cultivar interactions were significant for most traits, but the fertilizer level x cultivar and year x fertilizer level x cultivar interactions were not significant. Days to maturity, plant height, panicle per m2, and grain yield increased with increasing fertilizer levels during the two wet seasons. The grain yield of rice hybrids (bred by the International Rice Research Institute) was not significantly higher than that of the check cultivar widely grown in Senegal. The assessment of other rice hybrid germplasm showing more adaptability to low fertilizer levels will facilitate further hybrid cultivar development in Africa

Implications of farmer perceived production constraints and varietal preferences to pearl millet breeding in Senegal

Pearl millet ( Pennisetum glaucum L.) plays a critical role in smallholder food security in sub-Saharan Africa. The production of pearl millet has, however, stagnated or even declined due to several factors. The objective of this study was to assess farmer perceptions on production constraints and varietal preferences in Senegal. A survey was conducted involving 150 randomly selected farmers from 15 villages, in five representative rural communities of Senegal. A semi-structured questionnaire was used, supplemented by focus group discussions. Results revealed that parasitic Striga weed was the most constraining factor to pearl millet production across the rural communes. This was followed by low soil fertility and insect pests in that order. Other constraints included lack of machinery for sowing, plant diseases, drought, seed-eating birds, limited access to land for pearl millet cultivation and limited seed availability. Among the traits for varietal preference, farmers unanimously considered grain yield as the most important trait. Other important traits mentioned were adaptation to drought, adaptation to low soil fertility and earliness. These production constraints and varietal preference should be integrated in the profile of the national pearl millet breeding programmes in order to improve the productivity and adoption of bred-cultivars.Le mil est une importante culture c\ue9r\ue9ali\ue8re et joue un r\uf4le essentiel dans la s\ue9curit\ue9 alimentaire de la plupart des producteurs de l\u2019Afrique subsaharienne. Cependant, la production est oscillante et faible en raison de plusieurs facteurs. Une \ue9tude a \ue9t\ue9 conduite pour \ue9valuer la perception des producteurs sur les contraintes limitant la production du mil et leurs pr\ue9f\ue9rences vari\ue9tales au S\ue9n\ue9gal. Une enqu\ueate avec150 producteurs s\ue9lectionn\ue9s al\ue9atoirement a \ue9t\ue9 men\ue9e dans 15 villages situ\ue9s dans cinq communaut\ue9s rurales du S\ue9n\ue9gal. Une \ue9valuation rurale participative et des enqu\ueates ont \ue9t\ue9 men\ue9es. Les r\ue9sultats ont montr\ue9 que le Striga est le facteur majeur qui limite la production de mil au niveau des diff\ue9rentes communaut\ue9s rurales. Les autres contraintes rencontr\ue9es dans les communes rurales \ue9taient le manque de machines pour le semis, les maladies, la s\ue9cheresse, les oiseaux granivores, l\u2019acc\ue8s limit\ue9 \ue0 la terre et la faible disponibilit\ue9 des semences de vari\ue9t\ue9s am\ue9lior\ue9es. Les producteurs ont unanimement consid\ue9r\ue9 le rendement en grains comme le trait le plus important dans le choix d\u2019une nouvelle vari\ue9t\ue9. Les autres traits jug\ue9s important sont l\u2019adaptation \ue0 la s\ue9cheresse l\u2019adaptation \ue0 la faible fertilit\ue9 des sols et la pr\ue9cocit\ue9. Ces contraintes de production et pr\ue9f\ue9rences vari\ue9tales doivent \ueatre incluses parmi les objectifs du programme national de s\ue9lection de mil pour am\ue9liorer la productivit\ue9 et le taux l\u2019adoption des nouvelles vari\ue9t\ue9s

Performance of dual-purpose pearl millet genotypes in West Africa: Importance of morphology and phenology

Pearl millet ( Pennisetum glaucum (L.) R. Br.) is a cereal crop vital for food security in West and Central Africa. Its byproducts also serve as fodder for livestock, especially during dry seasons. The objective of this study was to evaluate selected genotypes from West African pearl millet breeding programmes, for dual-purpose (grain and fodder) and elucidate prospects for future breeding. A total of 83 open-pollinated varieties (OPVs), five composites, six landraces, one synthetic and five hybrids were evaluated at 14 environments in Burkina Faso, Mali, Niger and Senegal during the rainy seasons of 2015 and 2016. Combined analysis of data revealed significant differences among genotypes and prevalence of high genotype-by-environment interaction effects. Two stability analyses models consistently indicated that genotypes 10 (SMILBF10), 14 (SMILBF14) and 39 (SMILML5) were widely adaptable across the region. Plant height, panicle length and panicle yield showed significant positive correlations with grain yield; while days to flowering was negatively correlated. Positive correlation between grain and fodder yields indicate possibility for simultaneous improvement involving the two important traits. This result suggests that germplasm exchange and regionally integrated breeding programmes are important for the identification of widely adapted dual-purpose varieties of pearl millet, particularly in West African drylands.Le mil\ua0\ue0\ua0chandelle ( Pennisetum glaucum (L.) R. Br.) Est une c\ue9r\ue9ale vitale pour la s\ue9curit\ue9 alimentaire en Afrique de l\u2019Ouest et centrale. Ses sous-produits servent \ue9galement de fourrage pour le b\ue9tail, en particulier pendant les saisons s\ue8ches. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer des g\ue9notypes s\ue9lectionn\ue9s \ue0 partir des programmes de s\ue9lection du mil\ua0\ue0\ua0chandelle d\u2019Afrique de l\u2019Ouest, pour l\u2018 usage double (c\ue9r\ue9ales et fourrage) et d\u2019\ue9lucider les perspectives de s\ue9lection dans le future. Les 83 vari\ue9t\ue9s \ue0 pollinisation libre (OPV), cinq composites, six vari\ue9t\ue9s locales, une synth\ue9tique et cinq hybrides ont \ue9t\ue9 \ue9valu\ue9s dans les 14 environnements au Burkina Faso, au Mali, au Niger et au S\ue9n\ue9gal pendant les saisons des pluies de 2015 et 2016. L\u2018 analyse combin\ue9e des donn\ue9es ont r\ue9v\ue9l\ue9 des diff\ue9rences significatives entre les g\ue9notypes et la pr\ue9valence des effets \ue9lev\ue9s d\u2019interaction g\ue9notype-par-environnement. Deux mod\ue8les d\u2019analyses de stabilit\ue9 ont syst\ue9matiquement indiqu\ue9 que les g\ue9notypes 10 (SMILBF10), 14 (SMILBF14) et 39 (SMILML5) \ue9taient largement adaptables dans toute la r\ue9gion. La hauteur de la plante, la longueur de la panicule et le rendement de la panicule ont montr\ue9 des corr\ue9lations positives significatives avec le rendement en grains; tandis que les jours avant la floraison \ue9taient corr\ue9l\ue9s n\ue9gativement. Une corr\ue9lation positive entre les rendements en c\ue9r\ue9ales et en fourrage indique la possibilit\ue9 d\u2019une am\ue9lioration simultan\ue9e impliquant les deux caract\ue8res importants. Ce r\ue9sultat sugg\ue8re que l\u2019\ue9change de mat\ue9riel g\ue9n\ue9tique et les programmes de s\ue9lection int\ue9gr\ue9s au niveau r\ue9gional sont importants pour l\u2019identification de vari\ue9t\ue9s \ue0 l\u2018 usage double largement adapt\ue9es de mil \ue0 chandelle, en particulier dans les zones arides d\u2019Afrique de l\u2019Ouest

Genomic diversity in pearl millet inbred lines derived from landraces and improved varieties

Background: Genetic improvement of pearl millet is lagging behind most of the major crops. Development of genomic resources is expected to expedite breeding for improved agronomic traits, stress tolerance, yield, and nutritional quality. Genotyping a breeding population with high throughput markers enables exploration of genetic diversity, population structure, and linkage disequilibrium (LD) which are important preludes for marker-trait association studies and application of genomic-assisted breeding. Results: Genotyping-by-sequencing (GBS) libraries of 309 inbred lines derived from landraces and improved varieties from Africa and India generated 54,770 high quality single nucleotide polymorphism (SNP) markers. On average one SNP per 29 Kb was mapped in the reference genome, with the telomeric regions more densely mapped than the pericentromeric regions of the chromosomes. Population structure analysis using 30,208 SNPs evenly distributed in the genome divided 309 accessions into five subpopulations with different levels of admixture. Pairwise genetic distance (GD) between accessions varied from 0.09 to 0.33 with the average distance of 0.28. Rapid LD decay implied low tendency of markers inherited together. Genetic differentiation estimates were the highest between subgroups 4 and 5, and the lowest between subgroups 1 and 2. Conclusions: Population genomic analysis of pearl millet inbred lines derived from diverse geographic and agroecological features identified five subgroups mostly following pedigree differences with different levels of admixture. It also revealed the prevalence of high genetic diversity in pearl millet, which is very useful in defining heterotic groups for hybrid breeding, trait mapping, and holds promise for improving pearl millet for yield and nutritional quality. The short LD decay observed suggests an absence of persistent haplotype blocks in pearl millet. The diverse genetic background of these lines and their low LD make this set of germplasm useful for traits mapping

Ethnobotanical study of cowpea (Vigna unguiculata (L.) Walp.) in Senegal

Open Access Article; Published online: 05 Feb 2022Cowpea (Vigna unguiculata) plays a key role in family farming systems in Senegal. It makes an essential contribution to economic, nutritional and food security. Although it is crucial, little is known about how farmers classify the diversity of local varieties or about the social practices associated with them. The aim of this study is to characterize the farming practices associated with growing cowpea in Senegal. Surveys were conducted involving 335 rural farmers living in 37 villages, spread across seven regions that produce cowpea. An average of ten farmers were randomly selected in each village. The results reveal that cowpea is a key feature of cropping systems in the studied area. Our findings highlight the high diversity of local cowpea varieties with 59 local names inventoried. In 75% of cases, the name refers to the seed’s morphology or color. Cowpea production is more diverse in Diourbel and Louga and less diverse in the south. More than half the farmers (57%) acquired their cowpea seeds (early, semi-early and late maturity varieties) outside their village, either from markets, seed suppliers or NGOs. This new understanding of farmers’ expertize in the management of cowpea and its local variability will help to valorize local diversity in breeding programs

Effect of planting date on growth and grain yield of fonio millet (Digitaria exilis Stapf) in the Southeast of Senegal

A field experiment was carried out during the rainy cropping seasons of 2010 and 2011 in Southeastern Senegal. The study aimed at investigating the effects of sowing dates on plant growth and grain yield of fonio millet (Digitaria exilis Stapf). Seven planting times (from early July to mid August with 7-day interval) were laid out in a randomized complete block design. In general, plant growth and grain yield were significantly better for the early July sowing dates compared to other sowing dates. However, tillering capacity and grain size were not influenced by the sowing date. Highest grain yields were obtained on 15-July planting date with an average of 1,111 kg ha-1 in 2010 and 1,269 kg ha-1 in 2011. Compared to this planting date, the delay in sowing reduced grain yield by 50% in 2010 and 87% in 2011. Detrimental high rains to seedling vigor, decreasing sunshine during the plant growth, and rain deficit during the reproductive phase were among the main limiting factors for late sowings. Hence, the first fortnight of July could be recommended as optimal sowing period for early maturing cultivars of fonio in Southeastern Senegal.Key words: Fonio, Digitaria exilis, sowing date, growth, yield, Senegal

Assessment of Rice Inbred Lines and Hybrids under Low Fertilizer Levels in Senegal

This research was conducted at the Africa Rice Sahel Regional Station (near Saint Louis, Senegal) during two wet seasons (i.e., July to November) in 2010 and 2011 with the aim of assessing the performances of introduced hybrid cultivars along with an inbred check cultivar under low input fertilizer levels. The five treatments used in this study were (a) the control (without any fertilizer application), (b) 37.5–4.4–8.3 kg N–P–K ha−1, (c) half of recommend application in Senegal (75–8.75–16.5 kg N–P–K ha−1), (d) 112.5–13.3–24.8 kg N–P–K ha−1, and (e) the recommended application in the country (150–17.5–33 kg N–P–K ha−1). There were significant year and cultivar effects for all traits. The fertilizer levels affected significantly most traits except panicle length and 1000-grain weight. The year × fertilizer level and year × cultivar interactions were significant for most traits, but the fertilizer level × cultivar and year × fertilizer level × cultivar interactions were not significant. Days to maturity, plant height, panicle per m2, and grain yield increased with increasing fertilizer levels during the two wet seasons. The grain yield of rice hybrids (bred by the International Rice Research Institute) was not significantly higher than that of the check cultivar widely grown in Senegal. The assessment of other rice hybrid germplasm showing more adaptability to low fertilizer levels will facilitate further hybrid cultivar development in Africa

Exploring the agricultural landscape diversity-food security nexus: an analysis in two contrasted parklands of Central Senegal

International audienceCONTEXT: Fostering diversity within agricultural systems can substantially contribute to improved food security among smallholder farmers. Agroforestry parklands are diverse agricultural landscapes where trees can provide an array of ecosystem services. Previous studies analyzing the agricultural landscape diversity-food security nexus in agroforestry parklands have only considered tree cover. OBJECTIVE: We propose an original empirical approach that combines the analysis of spatial data on agricultural landscape diversity with agricultural field monitoring and household surveys. These three sources of data were used to scrutinize the direct and indirect contributions of agricultural landscape diversity to food availability and food access. METHODS: Millet yield was used as a proxy for food availability, and household food access was approximated using the Household Food Insecurity Access Scale (HFIAS) indicator. Two contrasted agroforestry parklands of Central Senegal were chosen as case studies. Firstly, we used a Gradient Boosting Machine (GBM) algorithm to disentangle the relative contribution of landscape diversity, biophysical and crop management variables in explaining millet yield variability. Secondly, we investigated the pathways linking agricultural landscape di-versity to HFIAS using a Correlation Network Analysis (CNA). RESULTS AND CONCLUSIONS: The GBM model explained 77% and 84% of millet yield variability for the two parklands, respectively, with landscape diversity variables accounting for 53% and 47% of relative influence. Among the landscape diversity variables, tree species richness and tree density were the most important ones. Millet yield was positively associated with tree density in the Nioro site until a threshold of 5 trees/ha, and with tree species richness in the two sites. The CNA showed that greater tree cover and larger tree patches were moderately correlated with HFIAS. This suggests that tree species with large crown, as it the case for most fruit bearing tree species in the region, are the main species contributing directly to food access. Agricultural land-scape diversity contributed mainly indirectly to household food access through an "agroecological pathway", i.e. by the provision of ecosystem services regulating and supporting crop production. SIGNIFICANCE: Using an integrated landscape approach relying on up-to-date remote sensing data and recent advances in data analysis methods, our study shows that tree species diversity matters as much as the amount of tree cover for the production of food, and it can contribute to improve food security. We bring a more nuanced picture of the contribution of agricultural landscape diversity to food security suggesting that land management policies supporting food security should consider both tree density and tree species diversity to optimize the co -benefits of trees for the different food security dimensions