Alam, S.Hojai, Nehail2020-06-112020-06-112019-07http://krishikosh.egranth.ac.in/handle/1/5810147480An experiment entitled “Study on the diversity of Colocasia germplasm of Dima Hasao District of Assam” was carried out during the period of 2017-19. A total of 16 germplasms were collected from the five blocks of the district namely Harangajao, Mahur, Maibang, Diyungbra and Sangbar. The Morphological study of the cultivars was done in the Experimental Farm and their taxonomic identification was carried out. The biochemical analysis of the cultivars was done in the laboratory. A total of 16 different cultivars were evaluated for their morphological traits with three replications in Randomized Block Design. The ethno botanical study was conducted in Dima Hasao district. The mean performance of growth and yield parameters revealed that the cultivar Thaklong-1 registered the maximum plant height (138.67 cm), plant girth (23.13 cm), corm length (48.95 cm), weight of corms per plant (2250 g), weight of cormels per plant (846.67 g), yield per plant (3.36 kg). Similarly, biochemical analysis reflected highest amount of starch (77.9%), fat (1.11%), ash (7.61%) and iron (10.56 mg/100g) content in the cultivar Thaklong-1. However, the highest crude protein (5.32%) was found in cultivar Tharujung. The calcium oxalate was found highest (0.1%) in cultivar Thabasha. The highest number of suckers (13.56 numbers per plant) was observed in cultivar Thagajao-2. Maximum number of corms (2.56 numbers per plant) was found in Cultivar Thaklong-galao whereas cultivar Thagajao-2 was recorded with maximum number of cormels i.e. 23.92 numbers per plant. The variation in leaf characters of the cultivars were also observed during study period. It was observed that out of 16 cutivars, 87.50 per cent cultivars exhibited erect apex down type of leaf orientation. Maximum colour of the petiole junction was found to be green (37.5 %) and purple colour (37.5 %). 75 per cent of the cultivars were found to have green main vein colour. Most of the cultivars (62.5 %) exhibited undulated type of leaf margin and highest leaf blade margin colour was found to be yellow (37.5 %). Among the all cultivars, majority of the cultivars i.e. 56.25 per cent exhibited purple colour in upper portion of petiole, while 75 per cent of the cultivars were found to have green colour in the lower portion of the petiole. The maximum(. 43.75 %) cultivars had red petiole junction colour in the dorsal side of the leaf. The yellow main vein colour in the dorsal side of the leaf was found to be maximum (43.75%) among the cultivars. Taxomomic study revealed that the cultivars Thagajao, Thaklong galao, Thahon and Tharujung belonged to species Colocasia esculenta whereas only Thaklong belonged to the species Colocasia antiquorum. Ethno botanical study revealed that majority (44.17%) of the respondents was found to use taro in the district. Most of the respondents (52.5 %) cultivate taro for purpose. Majority of the respondents (50.83 %) grow taro mostly in small size land holding. 67.5 per cent of the respondents sold their produce in nearby markets. Taro was mainly grown in mixed cropping system which acounted 53.33 per cent of the respondents. The study also revealed that the respondents use petiole (53.33%), leaf (20%), and corm (15%) for medicinal purpose. Only 11.67 per cent respondents were found to have no knowledge about the medicinal uses of taro. Based on the key informants, the preferential ranking of the cultivars were: Thaklong galao> Thaklong khasiba> Thaklong 1 which ranked first,second and third respectively.Thesis