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Jatropha curcas L. has been promoted as a “miracle” tree in many parts of the world, but recent studies have indicated very low levels of genetic diversity in various landraces. In this study, the genetic diversity of landrace collections of J. curcas was compared with the genetic diversity of the species from its native range, and the mating system was analyzed on the basis of microsatellite markers. The genetic diversity parameters were estimated, and analysis of molecular variance, principal coordinate analysis, and unrooted neighbor‐joining tree were used to describe the relationship among populations. Results confirmed very low genetic diversity in African and Asian landraces. Mexican populations from the regions of Veracruz, Puebla, and Morelos were also found to have low levels of diversity (mostly monomorphic), while populations from Chiapas were polymorphic with an expected heterozygosity between 0.34 and 0.54. Bayesian analysis showed differentiation according to geographic locations, which was confirmed by principal coordinate analysis and neighbor‐joining tree. Estimations of outcrossing rate of individual families from Chiapas showed that some mother trees were mainly outcrossing. Mating system could not be estimated in the landraces from Mali and populations from Veracruz, Puebla, and Morelos (Mexico), as these were highly monomorphic. The observed low level of genetic diversity in some of the populations and landraces suggests that breeding programs should test for genetic variation and heritability in relevant quantitative traits and estimate if sufficient gain can be expected from traditional testing and selection. Diversification of the local gene pools may be considered for breeding and selection.

This study carried out at the ICRISAT research station of Sadoré in Niger aimed at determining the impact of placed application technique of Jatropha oilcake on millet agronomic parameters. The experimental design was a randomised blocs including five treatments and four replicates. Control was plots without fertilizer while J_100 g, J_200 g , and J_300 g were plots receiving 100 g , 200 g and 300 g of Jatropha oilcake respectively per seed hole and the plots NPK_6 g were receiving 6 g of NPK (15, 15, 15) per seed hole. ANOVA test was used for data analyses. Only the Control had significantly low number of tillers. At the end of the vegetative period J_300 g has the highest plants. J_300 g induced 196% increase of grain yield compared to the Control. The substitution of NPK (15,15,15) by 100 g, 200 g and 300 g of Jatropha oilcake per seed hole induced 79-52.93%, 92-72.23% and 152-100.65% increase of grain yield respectively compared to the Control in 2009 and 2010. With regard to the grain yield in 2009 and 2010, 100 g of Jatropha cake per seed hole can replace the current 6 g (NPK) per seed hole.

Parkia biglobosa is a traditional economic tree legume of considerable multipurpose importance in the sudano-sahelian region in Africa. The species grows in multiple climatic zones with precipitation ranging from 600 to 2,500 mm a year and its natural distribution extends from Senegal and Guinea in West Africa to Uganda in Central Africa. In the present paper, a range wide sample of 25 provenances of P. biglobosa was tested in Burkina Faso, West Africa at two sites; Gonse (latitude 12°25 0 N; longitude 1°20 0 W; altitude 280 m) in the north-sudanian zone and at Dinderesso (latitude 11°18 0 N; longitude 4°35 0 W; altitude 425 m) in the south-sudanian zone. Based on analysis of survival and growth traits, we provide evidence of substantial genetic differentiation between P. biglobosa populations within West Africa. Height growth was best at Gonse, while the survival rate was higher at Dinderesso (61%) compared to Gonse (35%). Links between geographical parameters and the provenances performance were significant, and interesting geographic patterns were observed. Our results point towards superior fitness of the local Burkina Faso populations, and we speculate that presence of a continuum of locally adapted populations can be a part of the explanation for the species' ability to thrive under quite different climatic conditions across West Africa. Based on the findings, we suggest recommendations for seed deployment and conservation strategies of the species in the West African Sahel. This is particularly important when considering the on-going climate change.

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