The main mission of the division of Crop Improvement is the development of new varieties of tropical tuber crops which cater to the diverse needs of different clientele groups. A total of 5000 germplasm collected from different parts of India and abroad which represents the rich diversity of all the tropical tuber crops is being maintained both as field gene bank as well as in vitro active gene bank. About 40 varieties of the different tuber crops have been released by this division. These new varieties have some important attributes like high yield, high starch content, tolerance /resistance to different pests and diseases, good culinary properties, adaptability to different soil conditions etc. Different advanced biotechnological tools are also being used in this division for developing improved varieties of tuber crops.
Systematic efforts during the past five decades have led to the release of 47 varieties of tuber crops viz., 12 in cassava, 16 in sweet potato, 10 in yams, 2 in Amorphophallus, 6 in Colocasia and 1 in Coleus. The short duration cassava varieties Sree Jaya and Sree Vijaya are ideal for cultivation in paddy fallows of Kerala. The two high yielding varieties of sweet potato, Gouri and Sankar released by the Regional Centre, Bhubaneswar are suited for cultivation in the Eastern and North Eastern States. 'Muktakeshi" a taro variety released from the Regional Centre is resistant to taro leaf blight disease with an average tuber yield of 25-30 t ha-1 with excellent cooking quality. Sree Dhanya is a novel dwarf statured white yam which reduces (@40%) the cost of cultivation due to its non-climbing habit. Sree Shilpa, with its medium sized, smooth and oval tubers and n excellent cooking quality, is the first hybrid of greater yam produced in the world. Sree Padma is an elephant foot yam variety with high yield (41 t ha-1) combined with good cooking quality. Sree Athira is the first genetically improved elephant foot yam variety and Sree Kiran is the first hybrid taro variety released in India, which have recorded higher tuber yield. A decade long evaluation of cassava germplasm at CTCRI resulted in the identification of an exotic breeding line Mnga-l, field tolerant to cassava mosaic disease, which was released as the first CMD resistant variety in India. Sree Harsha, the triploid cassava with high yield (35-40 t ha-1) coupled with high starch content (38-41%) is ideal for cultivation in the industrial belt of Tamil Nadu and Andhra Pradesh. A high carotene sweet potato variety Sree Kanaka (ß-carotene 9-10 mg/100 g FW) was released for popularizing in poverty stricken, nutrient deficient regions of the country.