SOIL PROPERTIES AND AGRONOMIC EVALUATION OF TOMATO LINES (SOLANUM LYCOPERSICUM L.) IN THE NORTHWEST REGION OF GABON

Abstract

The availability of tomato seeds adapted to local production conditions remains one of the major constraints for a sustainable tomato industry in Gabon. An agro-morphological characterization of ten tomato lines enabled us to assess their potential on the soil of the north-western region of Gabon. At this end, the properties of the soil were analyzed on the one hand, then, agronomic parameters of the tomato lineswere assessed on the other. Univariate and multivariate analyses of agronomic data were carried out using R software. Granulometric analysis revealed that the soil had a silty-sandy structure (29% coarse silt, 28.71% coarse sand). The mineralogical composition shows an assimilable phosphorus content of 15.51ppm and concentrations (in meq/100g) of potassium, calcium, sodium and magnesium of 0.41, 0.99, 0.32 and 0.60 respectively. For agronomic results, flowering time ranged from 26 to 36 DAS and first harvests from 70 to 84 DAS. Line L1 was the earliest and L9 the latest. For the yield, lines L4 (26.7 t/ha) and L8 (20.5 t/ha) were the most productive. The fruits with the best sizes were those of lines L2 (87.7 g) and L4 (86.6 g). Lines L1, L4, L5 and L8 were the firmest. The various diseases observed were downy mildew, spoon yellows and apical necrosis, with a moderate severity index (23,08 %) for all lines. These results show the agronomic performance of certain tomato lines on the sandy-loam soils of Gabon and for varietal improvement programs to increase tomatoes productivity in Gabon.