Crop Production

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.

Crop Protection

On farm experiments were conducted at Salem, Tamil Nad and in Guntur Andhra Pradesh for management of soil borne diseases through bioformulation. Significantly higher tuber yields were obtained for the treatments where Trichoderma viride along with N- fixing bacteria or AM fungi were applied. All the microbial treatments significantly reduced tuber rot incidence in cassava compared to control where no microbial culture was applied. Infectious clone
of Sri Lankan Cassava Mosaic Virus (SLCMV) has been developed which could be used for challenge inoculation of transgenic cassava plants.

Crop Utilization

Production of cassava-cereal flour extrudates was perfected. Extrudates were prepared from cassava blended with corn flour, maida, wheat flour and finger millet and nutrition facts determined extrudates were also made from
Amorphophallus flour and blends of cassava with cotton seed cake. Extrusion parameters were optimized for the production of cassava-coconut powder extrudates and products with low bulk density, high porosity and low hardness could be obtained from cassava-coconut powder in the 90:10 ratio. Expansion ratio was the highest for 95:5 blends extruded at 180°C die temperature.

Crop Improvement

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.