CTCRI has taken up several missions during the period under report. In tune with its vision the studies were focussed on genetic improvement of tuber crops, development of better management techniques for disease and pest resistance, organic farming technology, bioactive principles in tuber crops, transfer of technologies and large scale production of quality planting materials. Significant contributions made from the Institute and externally funded research projects in the research front include development of mosaic resistant cassava (CMR) lines and identification of genotypes for hilly tracts of Tamil Nadu, identification of cassava genotypes for high productivity and high starch, characterization of drought responsive genes in cassava, transgenic research for developing mosaic resistance, identification of drought tolerant genotypes, identification of most K efficient genotypes and development of bioformulation and microbial treatment for controlling tuber rot in cassava, development of virus free cassava variety H-226 through chemo and thermotherapy, production of cassava-flour extrudates, development of high protein and dietary fiber enriched pasta from cassava, development of starch-graft and superabsorbant polymers, efforts for commercialization and popularization of processing technologies for cassava based value added products and development of processing methods in cassava leaves, identification of high yielding sweet potato genotypes with high carotene, research on emerging viruses in sweet potato, yams and elephant foot yam, simulation modeling in sweet potato, high yielding genotype for saline tracts of West Bengal, development of biofilm from sweet potato starch, identification of putative thermotolerant yeast strains for bioethanol production from sweet potato starch, somatic embryogenesis and regeneration in elephant foot yam, organic farming for increasing productivity in elephant foot yam, development of biofertilizer to substitute chemical fertilizer, identification of plant growth promoting microorganisms, research on development of virus free greater yam, molecular charcaterization of fungal diseases in tuber crops, identification of antineoplastic molecules associated with bacteria from entomopathogenic
nematodes and new bioactive molecules from bacteria associated with novel entomopathogenic nematodes and identification of constraints for tuber crops production and processing technologies and researchable issues. A large quantity of disease free quality planting material of different tuber crops have been produced and distributed to farmers, Govt. Horticulture Departments, NGO’s and other developmental agencies.

CMR – 1, a CMD resistant line of cassava derived from the cross between the resistant variety, Sree Padmanabha and an indigenous accession CI –732, was selected through farmers’ participatory on farm trials conducted at Erode distrct, Tamil Nadu for its high extractable starch content (28.6%), high yield (60 t ha-1) and disease resistance. Three cassava hybrid lines viz., CMR – 3, CMR – 63, and CMR – 70 with extractable starch content of 24.6 – 25.8% were identified as promising lines for the irrigated plains of Tamil Nadu, Four CMD resistant, cassava hybrid lines, viz., CMR – 42, CMR – 55, CMR – 68 and CMR – 63 with 24 – 28% extractable starch content were found suitable for the hilly tracts of Tamil Nadu through farmers’ participatory on farm trials conducted in Kadambur hills. Four triploid hybrids of cassava were found to be early maturing with tuber yield ranging between 32.5 and 38.6 t ha-1 with extractable starch content ranging between 28.5 and 30.0%. Triploid cassava selection 4-2 is cultivated in nearly 200 ha in Salem, Dharmapuri and Namakkal districts of Tamil Nadu. At HQ, 1669 cassava accessions
are maintained.

A survey conducted in the cassava growing
fields of Salem and Namakkal districts in Tamil Nadu revealed that farmers practice upto 5 manual weedings for which they spend about Rs 10500 ha-1 which is nearly 50% of labour cost involved. Here, they do not use weedicides or any mechanical device for weeding cassava fields. In the experimental plot at Panamarathupatti, 14 species of weeds were found out of which Cyperus rotundus, Cyanodon dactylon and
Panicum javanicum are the predominant. Within 2 months, weed population increased from 44.8 to 78.1 m-2 and dry weed weight increased from 13.3 g m-2 to 86.5 g m-2. During the first year sequential crop of vegetable cowpea (var. Pusa Komal) was found to be more compatible with short duration cassava under full dose of fertilizers.