In India, of late much emphasis is being given for bivoltine silkworm rearing to boost up the quality silk production matching international standards. Indian sericulture is dominated by the usage of only one or two bivoltine hybrids, either double/single, that are developed for usage under optimal conditions particular for favourable seasons only. There is a requirement for the development of silkworm double hybrids for commercial exploitation and therefore, attempts are being made to develop bivoltine silkworm hybrids. Earlier on these lines had resulted in the development of bivoltine hybrids and these hybrids have shown minimum impact on the Indian sericulture industry. Keeping this in view, an attempt has been made to develop bivoltine double hybrids tolerant to high temperature with disease resistance. After the screening for high temperature and disease tolerance, 10 promising stocks, five each of oval (APS67, APDR105, APS27, APSHTO5 & AP71) and peanut (APS12C, APS50, APS20, CTIPP & AP72), were selected as breeding resource material and a total of 20 oval foundation crosses and 20 peanut foundation crosses were prepared and reared. Out of which, 7 oval and 8 peanut FC’s were short listed and a total of 56 double hybrid combinations (Oval x Peanut type) were prepared and evaluated. During rearing, the important parameters viz., fecundity, yield / 10000 larvae by weight, pupation %, single cocoon weight, shell weight and shell ratio (SR %) measured. Two single hybrids, such as APS45 x APS12 and CSR2 x CSR4 and one double hybrid (CSR6 x CSR26) x (CSR2 x CSR27) were kept as control. The superiority of the hybrids was assessed through evaluation index method and heterosis is also calculated. The study identified two promising bivoltine double hybrids of (FC 25 x 90) and (FC 42 x 96) for large scale laboratory trials.
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