Comparative study on rearing performances of five eri silkworm eco-races during summer and autumn seasons in Nagaland

AbstractIn this investigation, five commonly found eco-races namely, Titabar, Borduar, Barpathar, Kokrajhar and Dhemaji were reared in two seasons i.e., Summer and Autumn, to identify the promising Eri silkworm eco-races. Parameters like larval duration, 5th instar larval length, width, weight and colour, pupal period, pupal length, width and weight, and growth index were observed. Among the selected eco-races, Barpathar and Borduar were found to have larger larval measurements and growth index with Borduar having longer pupal duration. The Barpathar eco-race during summer season and Borduar eco-race during autumn season showed promising rearing parameters including 5th instar larval length (7.41 and 7.68 cm), larval weight (6.98 and 7.46 g) and growth index (3.30 and 4.52%) respectively. The correlation matrix showed pupal duration to negatively correlate with growth index and other parameters. The Dhemaji and Kokrajhar eco-races showed poor performances, while Titabar performed moderately during both the seasons. The comparative rearing performances of all the eco-races were found to be superior during the autumn season than in summer. The mean growth index (by percent pupation) in autumn is also higher than the summer season by 42.23%.