Effects of genotypes and sowing methods on growth, phenology and yield of fonio (Digitaria exilis) in Benin

Fonio is an identity and orphan cereal of Africa whose production system has remained traditional. This work assessed the responses of selected genotypes of fonio to different sowing methods in Benin from 2018 to 2019. Split plot design with three replicates was used. Four genotypes from mass selection and two control varieties were randomly arranged in four planting modalities (ordinary broadcast sowing, continuous row sowing at inter-rows 20 cm (SLC20) and 25 cm (SLC25) and in seed hole sowing (SP25 x 20)). Agro-morphological data were collected and subjected to variance and multivariate analyses. On all traits, interaction (variety x sowing x year) was not significant. Other interactions (variety x sowing, variety x year, sowing x year) were significant on some morpho-phenological traits. Genotypes AS19-1-1, AS1 and 'Yoro' were the earliest, especially AS19-1-1 presenting sowing-heading cycle less of 65 days. Improved genotypes were the most grain yielding mainly AS15-1-1 (1056.5 kg/ha) showing an excess of 405.9 kg/ha compared to control 'Yoro' (650.9 kg/ha), the least performing. However, control 'Iporawan' was the most yielding in dry matter (>8000 kg/ha). Based on sowing methods, plant density was negatively correlated with tiller number. The best growth and grain yield performances were obtained in broadcast sowing and especially in SLC25 (911.4 kg/ha). Cropping systems in which the new genotypes (AS1, AS13-1, AS15-1-1, 19-6-1-1) sown in continuous rows at 20-25 cm apart, or by broadcasting, were better in terms of grain yield (971.7 kg/ha). These systems constitute cultivation innovation which will enable to optimize fonio production and bring added value.