Evaluation of Agronomic Performances of Eleven Ecotypes of Jatropha curcas L. Grown in Poor Soil of Batéké Plateau near Kinshasa (DRC)

RESUME

Description of subjet. Eleven ecotypes of Jatropha curcas L. collected in various agro-ecological regions of the DRC were cultivated near Kinshasa on very poor soil to identify elite germplasm.
Objective. The objective of this study is to evaluate the agronomic performance of 11 ecotypes of J. curcas grown on very poor soil on the Batéké Plateau near Kinshasa in order to select elite germplasm for breeding purpose.
Methods. The J. curcas seed sample collection was carried out in seven provinces of the DRC, from May to July 2009. Samples of collected seeds were sown in polythene bags. They were cultivated in a nursery (three months) from 5 July to 3 October 2009 in Mbankana. The plantation was laid out in a randomized complete block design (RBD) with three replicates at a density of 2 500 plants ha-1 (spacing of 2 m x 2 m) on land that was previously prepared after a fallow of five years. The total number of plants per ecotype varied from 20 to 36.
Results. After 42 months of cultivation, significant differences (p<0.05) were found for plant height (1.4±0.0 – 1.7±0.0 cm), collar diameter (6.8±0.6 – 8.9±0.4 cm), number of branches per plant (22.1±4,7 – 38.8±7.2), days to first flowering (236.3±5.7 – 273.0±5.7 days), fruit maturation duration (67.3±3,5 – 84,6±4.7 days), capsule abortion rates (21.0±3,7 – 32.6±3.0 %), number of capsules per plant (19.4±6.5 – 96.4±8.5), number of seeds per capsule (2.5±0.1 – 3,0±0.0), seed index (100 seeds weight) (48.7±1.8 – 79.1±1.1 g), dry seed yield (68.6±3.6 – 473.1±3.6 kg ha-1), oil content (23.3±4.0 – 35.1±1.8 %), content in mono-unsaturated fatty acids (45.2 – 49.5 %). No plant resistant to the main insect pests attacking J. curcas in the region was observed. The ecotype originating from Panu (Bandundu Province) showed by far the best performance for seed yield and seed oil content.
Conclusion. The existence of a large variability in yield components and quality of the oil opens up good prospect for obtaining J. curcas varieties adapted to the growing conditions of the region. Considering their growth attributes and yield potential, some of the collected ecotyps constitute very promising genetic stocks to start a breeding program of J. curcas.

Keywords : Ecotypes, Jatropha, Oil Yield, Elite, Kinshasa

Jean de Dieu Minengu, Patrick Mobambo, Guy Mergeaie