Agro-morphological and structural diversity of rice germplasm revealed by SSR markers in Benin Republic.

BACKGROUND: In developing countries, rice is a staple food and cash crop for the people. In Benin Republic, paddy rice production has increased over time. Accordingly, local varieties were replaced by improved varieties, leading unfortunatley to a loss of the diversity of Beninese rice germplasm. METHODS AND RESULTS: The investigation focused on the structure and genetic diversity of 72 rice accessions collected throughout 22 villages using 13 quantitative traits and 17 SSR markers. The descriptive analysis of the 13 quantitative parameters showed a significant difference among the accessions, with a grouping in three clusters. Group I (16.66% of samples) was composed of accessions with long, wide and thick grains alongside with four controls TOG5681, TOG5307, Azucena and Moroberekan. Group II (7% of samples) contained accessions with late vegetative cycle. Group III contained most of the accessions (76.39% of the samples), including accessions such as the CG14 and Nipponbare control lines, and almost all the improved varieties. The molecular analysis revealed a significant diversity (mean number of alleles: 4.47 with polymorphism information content of 0.633). Population structure based on molecular markers showed three primary populations with a mixture of phenotypic groupings at ΔK, K = 3. CONCLUSION: This study showed that Beninese rice germplasm was divided into two structures: phenotypically similar cultivars but genotypically distinct (homonyms), and phenotypically different cultivars but genotypically similar (synonyms). Some local cultivars such Bagou19, Bagou20 and Koud44 can be used for large scale production due to their agronomics and molecular traits. The molecular structure obtained in this investigation might be used for future conservation and breeding programs.

Impact of Seed Origin and Genetic Drift of Improved Rice Variety IR841 in Benin.

BACKGROUND: Rice production is important for food security in Benin, with a national production largely dominated by the cultivation of the aromatic ecotype IR841, by far the most appreciated by Beninese consumers. However, to maintain agronomical qualities of a given cultivar, the origin and quality of seeds are mandatory and at the heart of the maintenance of yield and of market requests. Following this idea, the objective of the current study was thus to investigate the genetic purity of IR841 varieties collected from rice producers across 22 villages in Benin in relation to their agronomical performances. RESULTS: For this, agromorphological evaluation of 72 accessions based on 13 quantitative descriptors followed by genotyping with the Illumina Infinium rice 7 K SNP array of 9 accessions was carried out in the presence of 2 controls. Agromorphologic as well as genetic and phylogenetic analyses revealed two groups, the first one Okouta97, Koum47, Nana30, Man118, Ang1 and control sample IR841-2) was characterized by seed accessions provided by the formal seed system, while the second (Koum53, Tchaka41 and Koud46) comprising seeds from local markets or from previous harvests and showing a depression in agronomic performances. CONCLUSION: We showed that IR841 seed purity is mandatory for the completion of agronomical performance, and that the farmers' choice of seeds must be guided and informed to ensure sustainability and food security.

Diversity, Physicochemical and Technological Characterization of Elite Cassava (Manihot esculenta Crantz) Cultivars of Bantè, a District of Central Benin.

Cassava is one of the staple food crops contributing significantly to food and nutrition security in Benin. This study aimed to assess the diversity of the elite cassava cultivars of Bantè district, determine the physicochemical properties of the most preferred ones as well as the sensory attributes of their major derived products (gari and tapioca), and compare them with the farmers' and processors' perception on their technological qualities. The ethnobotanical investigation revealed existence of 40 cultivars including 9 elites that were further classified into three groups based on agronomics and technological and culinary properties. Clustered together, cultivars Idilèrou, Monlèkangan, and Odohoungbo characterized by low fiber content, high yield of gari and tapioca, and good in-ground postmaturity storage were the most preferred ones. Their physicochemical analysis revealed good rate of dry matters (39.8% to 41.13%), starch (24.47% to 25.5%) and total sugars (39.46% to 41.13%), low fiber (0.80% to 1.02%), and cyanide (50 mg/kg) contents. The sensory analysis of their gari and tapioca revealed very well appreciated (taste, color, and texture) products by the consumers. The confirmation by scientific analysis of the farmers' perception on qualities of the most preferred cultivars indicated that they have good knowledge of their materials.

Genetic divergence in northern Benin sorghum (Sorghum bicolor L. Moench) landraces as revealed by agromorphological traits and selection of candidate genotypes.

Sorghum [Sorghum bicolor (L.) Moench] is an important staple food crop in northern Benin. In order to assess its diversity in Benin, 142 accessions of landraces collected from Northern Benin were grown in Central Benin and characterised using 10 qualitative and 14 quantitative agromorphological traits. High variability among both qualitative and quantitative traits was observed. Grain yield (0.72-10.57 tons/ha), panicle weight (15-215.95 g), days to 50% flowering (57-200 days), and plant height (153.27-636.5 cm) were among traits that exhibited broader variability. Correlations between quantitative traits were determined. Grain yield for instance exhibited highly positive association with panicle weight (r = 0.901, P = 0.000) and 100 seed weight (r = 0.247, P = 0.000). UPGMA cluster analysis classified the 142 accessions into 89 morphotypes. Based on multivariate analysis, twenty promising sorghum genotypes were selected. Among them, AT41, AT14, and AT29 showed early maturity (57 to 66 days to 50% flowering), high grain yields (4.85 to 7.85 tons/ha), and shorter plant height (153.27 to 180.37 cm). The results obtained will help enhancing sorghum production and diversity and developing new varieties that will be better adapted to the current soil and climate conditions in Benin.