When some one iterrupted me and told me that he has seen Jatropha growing on bare rocks I could not deny this fact but when people say its a plant for wasteland and Government of over 30 countries go after its mass plantation I feel scared as a botanist. The simple reason is that althogh this plant has the ability to grow in adverse climate that does not mean it will produce fruits also. Our experience of 25 years of work on Jatropha has proved that although it can grow below 300 mm rainfall also but it will need at least 400 to 600 mm of rainfall for bearing fruits.
There is a Jatropha belt globally but one has also to consider soil conditions, water availability , nutrient status, habitat and society of plants and microbes in totality. When Government of Rajashtan introduced biofuel authority it apparently lacked the core group which will assess the feasibility of its growth and productivity and advice accordingly.
Three basic things are very important for this plant
1. Good nutrition of Nitrogen Phosphorus and Potassium is important but the plant also needs Phosphorus for its growth and flowering. However a very healthy plant will not produce enough fruits and grow more and more to produce vegetative branches and leaves.
2. Un irrigated plants will also not bear fruits under sandy soil conditions during early bearing period. How and why unirrigated plants of Udaipur bear fruits has to be looked into the fact that the soil which is loamy to dark soil has enough organic carbon and water retention ability.
3. In our observations the plants which had more leaves had less flowers and vice versa but this was not always true.
4. Although plant bears a large number of flowers and sexes are separate the ration of male and female flowers is variable depending on season.
5. If the temperatures fall below 7 degree the flowering and fruiting is adversely affected and so is when temperatures rise in summers.

The plants needs more studies and sharing of experiences before jumping on the banwagon of Jatropha curcas. We have successfully made selections of 64 accessions out of which 4 are extremely good but in general the plant lack genetic variability and breeding process is slow .
There are hardly any convincing reports on high yields of this plants most the the data is internet data and real informations are lacking. During the course of 4 years we have generated enough data but to express it in scientific terms will take more time and patience and further studies for confirmation The plight is it takes 3 to 4 years for this plant to come to maturity and it needs another 3-4 years to complete studies on floral biology which is most important aspect to determine its yield potential in varied agroclimatic conditions.
Once we want to bring this plant to different habitats it will need great expertise and experiences - shared and original to make this plant a success.
I would welcome experiences for different regions who have actually grown this plant and obtained yields in habitats other than its natural climate and zones.
Another important aspect is also mycorrhizal associations and other fungal interactions .
The plant sap has pH as low as 2 to 3 and there remains to be seen what impact it has on soil.
This is not to discourage Jatropha growers but to caution them not to put all their eggs in one basket. Good luck Jatropha growers around the world.