~ 12 ~ Journal of Entomology and Zoology Studies 2015; 3(5): 12-19 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2015; 3(5): 12-19 © 2015 JEZS Received: 12-07-2015 Accepted: 13-08-2015 Dulur Brahma Department of Zoology, Bodoland University, Kokrajhar – 783370, India Ananta Swargiary Department of Zoology, Bodoland University, Kokrajhar – 783370, India Karabi Dutta Department of Zoology, Gauhati University, Guwahati – 781014, India Correspondence: Dulur Brahma Department of Zoology, Bodoland University, Kokrajhar – 783370, India A comparative study on morphology and rearing performance of Samia ricini and Samia canningi crossbreed with reference to different food plants Dulur Brahma, Ananta Swargiary, Karabi Dutta Abstract Samia ricini is a non-mulberry, multivoltine, domestic moth, reared indoor. S. canningi is wild, bivoltine silkworm. Both the varieties are found in North-eastern states of India. Castor (Ricinus communis; Euphorbiaceae) and payam (Evodia fraxinifolia; Rutaceae) are the host plants of S. ricini and S. canningi, respectively. S. ricini is susceptible to unhygenic and poor environmental conditions. The present study was designed to produce a crossbreed between S. ricini and S. canningi and to study the differences in morphological and economic parameters between the parents and crossbreed. Experimental results have shown that the rearing and economic performance of crossbreed showed superior quality compared to parental species. However, crossbreed showed better result in payam leaves. The present study therefore suggest that the S. ricini x S. canningi crossbreed can be commercialized which may be highly productive to sericulture industry. However, further study regarding the productivity and food plants need to established. Keywords: Samia ricini, Samia canningi, crossbreed Introduction Silk and sericulture has been a part of life and culture of the Indians. Today sericulture industry earns about 25 billion (2013-14) providing employment opportunity to approximately 7.85 million people in rural and semi-urban areas in India (Central Silk Board, 2015). The productivity of Sericulture mainly depends on high breeding stock of the silkworm. The hybridization is a technique to enhance the yield of silkworm and cocoon production. By crossing genetically distinct population and understanding the genetic mechanism of the silkworm, high yielding and disease tolerant races with distinct quantitative and qualitative traits can be achieved. The success in silkworm hybridization primarily depends on the selection of initial breeding materials followed by their effective utilization in different combinations to create genetic variability for selection [1] . In India, it is estimated that nearly 80% of the silk is produced by multivoltine × bivoltine hybrids where multivoltine races are used as female parent for commercial exploitation. The main reason attributed to this is that the contribution of bivoltine by virtue of its maternal inheritance may result in regular crop loss [2] . Suitable silkworm hybrids play a vital role in increasing the productivity and quality of silk which are important for sustainable sericulture industry [3] . Eri silkworm, Samia ricini is a domesticated multivoltine sericigenous insect largely reared by the farmers of North Eastern states of India, particularly Assam because of its easy rearing and availability of food plants [4] . S. ricini are susceptible to a disease flacherie. The productivity and quality of cocoon, however, depends upon quality food supply, favorable environmental conditions and utmost hygienic condition [5] . Scientists around the world are looking for silkworms which can withstand all the environmental conditions, resistant to diseases and easily cultivable and high productivity as well. Samia canningi is a wild variety of Eri silkworm with bivoltine nature that is susceptible to a bacterial disease called gracherie. In this connection, the possibility of enhancing the silkworm and cocoon production was experimentally attempted through crossing different variety of silkworms with selected traits. The present work was therefore designed to study the variation in morphology and productivity of S. ricini x S. canningi crossbreed and also to study variation in productivity as well as its adaptability to different diseases in relation to two food plants viz., castor (Ricinus communi; Family: Euphorbiaceae) and payam (Evodia fraxinifolia Hook; Family: Rutaceae).