Protocols for Micropropagation of Woody Trees and Fruits

MICROPROPAGATION OF CASHEW
shade and provided with drip irrigation. The survival at this stage was 100%
without any mortality.
9. Under the greenhouse conditions, the tissue culture derived plants are maintained
for 4 to 6 months until they are planted in the field in rainy season.
The approximate time required from explanting to planting varied from 40
to 50 weeks.
2.9. Field Planting and Evaluation of Micropropagated Plants
Micropropagated plants (40 to 50 weeks old) maintained in greenhouse are finally
planted in pits (75 cm 3 ) filled with soil and compost and rock phosphate added to
root zone (100 g/pit). If planted during rainy season additional irrigation is not
required; otherwise, hose or pot watering is required for initial establishment. The
establishment was found to be 100% in the micropropagated plants planted in field
(laterite soil) (Figure 1G).
In the first year of planting of micropropagated plants, 33% of the plants
flowered and in the second year 60% flowered and bearing of fruits was observed in
some tissue cultured plants of VRI-1 variety (Figures 1H, I). Flowering and fruiting
behavior was normal in micropropagated plants. Root-biomass of micropropagated
plants and grafted plants was studied by sectorial method of destructive sampling of
one-year-old trees and it was observed that root biomass of micropropagated plants
was four times that of grafted plants. The tissue culture plants had predominantly
lateral root system while the grafted plant had a strong tap root and poor lateral
root system.
3. CONCLUSION
Although micropropagation technique is available in cashew, it needs to be scaled
up before taking it up on a commercial scale besides working the production cost.
Micropropagation may be useful for producing clonal root stock and to multiply the
breeders stock at a faster rate. The technique needs to be perfected in shoot explants
of mature tree origin in order to have a wider application.
Acknowledgments. Authors thank profusely Dr. M.G. Bhat, Director, National Research
Centre for Cashew for his keen interest and encouragement. Thanks are also due to Mr. R.
Muthuraju for type scripting the manuscript. The authors wish to thank Dr. S. Mohan Jain and
his colleagues for their valuable suggestions and help.
4. REFERENCES
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Induction of somatic embryogenesis from nucellus-derived callus of Anacardium occidentale L. Sci.
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Boggetti, B., Jasik, J. & Mantell, S. (1999) In vitro multiplication of cashew (Anacardium occidentale L.)
using shoot node explants of glasshouse raised plants. Plant Cell Rep. 18, 456–461.
Cardoza, V. & D’Souza, L. (2000) Direct somatic embryogenesis from immature zygotic embryo of
cashew. Phytomorphology 50, 201–204.
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