ISCA Journal of Biological Sciences _________________________________________________ ISSN 2278-3202 Vol. 1(2), 69-72, June (2012) ISCA J. Biological Sci. International Science Congress Association 69 Short Communication Spring rearing performance by feeding temperate mulberry variety on bivoltine hybrid NB × SH6 of silkworm, Bombyx mori LSingh Amardev, Ahmed Farooq and Bandey Shamim AhmedDeptt. of Sericulture, Govt. Degree College, Poonch, J&K, INDIA Deptt. of Zoology, Govt. Degree College, Poonch, J&K, INDIAAvailable online at: www.isca.in (Received 23rd May 2012, revised 25th May 2012, accepted 26th May 2012)Abstract Two rearing performance of bivoltine hybrid viz., NB×SHwhich wasreared first time during the year 2011 and second time 2012 in the months of April-May (spring season) exhibited better performance. The data revealed that single cocoon and shell weight was found to be (1.78 and 1.81, 0.377 and 0.384) in the year 2011 and 12 respectively. Key wordsBivoltine, hybrid, season, spring rearing.IntroductionSilkworm has a large role in rural life in India being an insect of economic importance. The common silkworm Bombyx mori Linnaeus (Lepidoptera: Bombycidae) spins valuable silk fibre, making it one of the most beneficial insects to mankind, and is becoming an attractive multifunctional material for both textile and non textile uses. Almost all-commercial silk is made from cocoons spun by silkworms of the genus BombyxBivoltine silkworm rearing is a very complicated process, which requires various technical aspects, specific management skills, due understanding and experience. The practice of sericulture consist of two major activities viz., cultivation of mulberry plants for producing disease free crop leaf to the silkworm larvae and the rearing of silkworm larvae to produce the cocoons, which is the raw material for the silk reeling industry. Silkworm is an economical and helpful insect and is reared by many farmers throughout world. It is an important economic insect since it is the producer of silk. Success in sericulture depends largely on major factors like, breed, seed and feed. The silkworm breeds play an important role for high cocoon yield and silk quality. If the cocoons, which form the basic raw material for raw silk, are from bivoltine will definitely be superior with high silk content. Introduction of tropical bivoltine rearing practices in India is revolutionizing the bivoltine silk production in South India. The newly evolved bivoltine hybrids at various institutes are capable of producing higher cocoon yield with 2A to 3A grade silk and are popular among the farmers. The state of Jammu and Kashmir produces high grade quality bivoltine silk from hybrids. It ranks 5th in the country cocoon production and is leader in high quality bivoltine silk Normally single rearing is conducted in Jammu during March-April in sub-tropical areas. Now-a-days efforts are being made to enhance the cocoon crop production by introducing an additional commercial crop for autumn. From time to time various bivoltine silkworm hybrids have been recommended for commercial exploitation5-11 but the performance of these hybrids varies with varying atmospheric conditions.The state of Jammu and Kashmir with diverse climate conditions like sub-tropical in Jammu plain, warm temperate in Jammu hills and cool humid in Kashmir valley, make it ideally suitable to rear bivoltine races for production of quality bivoltine silk. In this context, present was carried to study the spring rearing performance of bivoltine hybrid NB×SH6 of silkworm, Bombyx mori L under sub-tropical climatic condition.Material and MethodsThe silkworm rearing of bivoltine hybrid NB×SH6 was carried out by feeding on Chakmajra a temperate variety of mulberry collected from nearby college ground during the months of April-May (spring season) for the year 2011 and 2012. Chawki silkworms (Approximately-5000 young silkworms) were obtained when they were just undergoing 1stmoult from the State Sericulture Department, Poonch (J&K). Recommended silkworm rearing method was adopted as suggested by12. The silkwroms were fed individual picked mulberry leaves up to 4th instars, and in the last instar shoot feeding method was adopted and two feeds were given in a day i.e., 10 A.M. and 6:30 P.M. preferably. The data of the economically important traits after harvesting on 7th day were recorded such as single cocoon weight, single shell weight, shell %, matured larval weight (10 larvae in gm) and total larval duration were collected and results are presented in the form of overall mean in tables (1-2) and figures (1-4). ISCA Journal of Biological Sciences ___________________ Vol. 1(2), 69-72, June (2012) International Science Congress Association Total larval duration for Instars Total Feeding period 1 st 2 nd 3 rd 4 th 5 th Total duration Total larval duration for the silkworm rearing conducted during the year 2012 Instars Total Feeding period 1 st 2 nd 3 rd 4 th 5 th Total duration Rearing performance by single shell weight (g) 1.76 20112012 0.372 0.374 20112012 Rearing performnace by single cocoon weight (g) ___________________ ______________________________ ______ International Science Congress Association Table-1 Total larval duration for the silkworm rearing conducted during the year 2011 Total Feeding period Moulting durations (days) 6days  2 days 6  2 days 1 days 5  2 days 2days 6  2 days 2  2 days 8  2 days Spinning (2 34days 7days Table-2 Total larval duration for the silkworm rearing conducted during the year 2012 Total Feeding period Moulting durations (days) 5 days  2 days 5days 1day 6days 1days 7days 2days 09days Spinning (2 32days 5 days Figure-2 Rearing performance by single shell weight (g) 1.771.781.791.81.811.78 1.81 Single cocoon weight (g) 0.374 0.3760.3780.380.3820.384 0.386  Single Shell Weight (g) Figure-1 Rearing performnace by single cocoon weight (g) ______ _______ ISSN 2278-3202 ISCA J. Biological Sci. 70 the silkworm rearing conducted during the year 2011 Moulting durations (days) days 1 days 2days days Spinning (2  2 days) 7days Total larval duration for the silkworm rearing conducted during the year 2012 Moulting durations (days) days 1day 1days 2days Spinning (2  2 days) 5 days 1.81 0.386 ISCA Journal of Biological Sciences ___________________ Vol. 1(2), 69-72, June (2012) International Science Congress Association Results and Discussion The spring rearing of silkworm is quite popular in the state of J& K in general and Poonch district in particular. The bivoltine hybrid NB×SH6 was first time reared in the year 2011 and same was reared in the current year 2012. Since this hybrid is also distributed to the farmers in the entire district wherever sericulture farmers is existed and it was imperative to assess the performance of the hybrid. The data regarding total larval duration for the year 2011 and 2012 showed that total feeding period was 34 and 32 days and moulting duration was recorded 7 and 5 days respectively, the slight variation is because of changing environmental conditio ns during the silkworm rearing as it prolonged the larval duration (table 1 and The rearing performance pertaining to single cocoon which is one vital trait for the farmers point of view as the cocoons are sold by weight only in the cocoon market and 21.16 21.17 20112012 46 20112012 Rearing performance by weight of ten ___________________ ______________________________ ______ International Science Congress Association The spring rearing of silkworm is quite popular in the state of K in general and Poonch district in particular. The bivoltine was first time reared in the year 2011 and same was reared in the current year 2012. Since this hybrid is also distributed to the farmers in the entire district wherever sericulture farmers is existed and it was imperative to assess the hybrid. The data regarding total larval 2012 showed that total feeding 32 days and moulting duration was recorded 5 days respectively, the slight variation is because of ns during the silkworm rearing and 2). The rearing performance pertaining to single cocoon which is one vital trait for the farmers point of view as the cocoons are sold by weight only in the cocoon market and it was found to be (1.81 and , 1.78g) for the year 2011 data regarding single shell weight was (0.384 (figure- 2). The results of shell percentage for the year 2011 12 depicted a value of 21.22 and good performance of this hybrid in the spring season might be due to suitability and congenial atmospheric condition prevailing while conducting the silkworm rearing. The results pertaining to weight of ten matured silkworm larvae was (49 and 47g) for the year 2011 and 12 (ConclusionThe bivoltine hybrid NB×SH when reared in the last two consecutive years and this hybrid can be exploited among farmers in the Poonch district of J& state for enhancing the productivity of cocoons. 21.17 21.1821.1921.2021.2121.22 \n \r 46 474849  \n\r\r \r \r  \rFigure-3 Rearing perfromance by shell % Figure-4 Rearing performance by weight of ten matured larvae ______ _______ ISSN 2278-3202 ISCA J. Biological Sci. 71 , 1.78g) for the year 2011 and 2012 (figure-1). The data regarding single shell weight was (0.384 and 0.377g) 2). The results of shell percentage for the year 2011 and and 21.18 % respectively. The good performance of this hybrid in the spring season might be due to suitability and congenial atmospheric condition prevailing while conducting the silkworm rearing. The results pertaining to weight of ten matured silkworm larvae was (49 f igure-4). exerted better performance when reared in the last two consecutive years and this hybrid can be exploited among farmers in the Poonch district of J& K state for enhancing the productivity of cocoons. ISCA Journal of Biological Sciences ______________________________________________________________ ISSN 2278-3202Vol. 1(2), 69-72, June (2012) ISCA J. Biological Sci. International Science Congress Association 72 Acknowledgment Authors are highly thankful to the Deputy Director, State Sericulture Development, Poonch (J&K) for supplying of young age silkworm larvae and other necessary materials for conducting of silkworm rearing in the second consecutive year also. 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