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 Growing
JATROPHA in Semi-arid India
The
criteria for success of a new agro-industrial crop are stability of
annual seed production and profitable seed yields. Irrespective of being
a xerophyte, the arid environment need not be ideal for commercial
planting since mechanisms that enable Jatropha to survive under stress
are not always compatible with those necessary for sustained production
as a commercial crop.
There is no denying that for good seed yield and oil content, soil
moisture and fertility levels are important. However, the phenology of a
prospective genotype has to synchronize with the rainfall pattern in a
given semi-arid situation like scanty rains in short spells and fewer rainy days.
 During recent germplasm screening, several genetic variants were
identified for responding differently to stress. The data on flower
initiation and male to female flower ratio, during the flowering cycle,
led to identification of early, mid-late and late genotypes. Further
evaluation and utilization of these variants in future breeding programs
shall be helpful in developing varieties suitable for different
agro-climates in the larger canvas of semi-arid India. Across the board,
such seasonal changes in oil and fatty acid profiles were also recorded
that could have bearing on the nature and use of Jatropha
oleo-chemicals.
Lack of uniform seed production and maturity cycle limit Jatropha
commercialization. Supplemental irrigation at flowering as well as the
effect of sudden withdrawal of irrigation, resulting in dehiscing and
senescence can drastically alter the flowering behavior, seed maturity
and yields.
 Years of growing experience has shattered the myth that "Jatropha is not
affected by major diseases or insect pests". Leaf spot, leaf rust, downy
and powdery mildews, stem and root-rot are few of the diseases in the
plantations. Seedling die-back and collar-rot are common in Jatropha
nurseries. The disease incidence can be severe when under irrigation
(prolonging the seasonal cycle) in semi-arid environments. However, most
of the pathogens can be controlled with application of KIRAN™ in
combination with other systemic fungicides.
Jatropha mosaic and bunchy top are two viral diseases so far identified
in Jatropha curcas plantations as well as wild stands. Application of
ZILLON™ is quite effective. Care must also be taken to propagate only
virus free planting material to restrict the disease spread.
Leaf minor, especially on tender foliage, weevils, shoot and root
borers, thrips and mites, and a variety of pests colonize leaves, tender
shots, floral buds and developing fruits in semi-arid plantations. Such
insect damage has been found to impare adversely the seedling growth and
crop establishment, and fruit & seed development. Repeat spraying 3-4
times during the a growing season may be required to limit any crop
damage.
While most of the diseases and pests seam to appear insignificant today,
propagation of cloned material and monoculture of Jatropha could
compound the problem quickly. Breeding for disease and pest resistance
need to be given due priority in future research programs.
Use of FYM mixed with VINGROW™ helps establishment of a robust and
healthy crop along with use of NPK and Magnesium and Zinc.
Although Jatropha seams to grow very well in calcareous soils with pH up
to 8.5, growth is restricted on acidic soils with pH below 5.2 or in
soils beset with high salinity.
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