Browsing by Author "NARAYANASWAMY, T. K."
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ThesisItem Open Access GENETIC ARCHITECTURE, HETEROSIS AND COMBINING ABILITY IN SILKWORM, Bombyx mori L.(University of Agricultural Sciences GKVK, Bangalore, 2009-09-15) ASHOKA, J.; NARAYANASWAMY, T. K.The investigations were carried out to study the combining ability and heterosis in multivoltine and bivoltine breeds through line × tester analysis. Twelve each of multivoltine and bivoltine breeds were reared and evaluated for sixteen quantitative traits. Among them six multivoltine viz., PM, BL43, APM1, MH1, TNW and Nistari and six bivoltine viz., CSR2, CSR4, APS4, APS5, APS8 and NB4D2 parents were selected as lines and testers respectively and 36 multivoltine × bivoltine crosses were prepared. The parents and 36 crosses were evaluated in three rearings conducted at College of Agriculture and Regional Agricultural Research Station, UAS Campus, Raichur during 2007-08 for 16 quantitative traits. D2 statistics results indicated that 24 breeds were grouped into five clusters and the intra cluster D2 distance ranged from 39.40 to 3176.83 implying the prevalence of intra cluster diversity. The magnitude of D2 values ranged from 139.34 to 4282.82 indicated a very high variability. Among the multivoltine × bivoltine crosses, the lines BL43 and MH1 (for eight traits each out of 16) and the testers APS4 and CSR4 (respectively for 5 and 6 traits out of 16) were found to be good general combiners. The cross, BL43 × APS4 was found to be good specific combiner (exhibited highest sca effects for 10 out of 16 traits) followed by PM × NB4D2, APM1 × CSR2 and APM1 × CSR4 (all three crosses exhibited highest sca effects for five traits each out of 16). The magnitude of standard heterosis in desirable direction was highest in BL43 × APS4 for nine traits followed by MH1 × APS5 (for five traits), MH1 × CSR4 and Nistari × CSR4 (for four traits each). Evaluation index revealed that the hybrid BL43 × APS4 ranked superior in eight instances followed by Nistari × CSR4, BL43 × NB4D2 along with APS-series breeds. Multivoltine lines, Nistari, TNW and PM / BL43 respectively ranked for six, five and four instances of superiority for duration and survival traits. Variance due to sca was higher than gca for majority of the traits indicating the predominance of non additive gene action in controlling majority of the traits studied. The hybrid BL43 × APS4, excelled in mean performance, standard heterosis and evaluation index values for most of the traits, followed by Nistari × CSR4. However, the crosses, PM × NB4D2, APM1 × CSR2 and APM1 × CSR4 have manifested highest sca effects for five traits each out of 16 studied.ThesisItem Open Access INDUCTION OF MALE STERILITY IN SILKWORM UZI FLY, Exorista bombycis (Louis) - A PARASITOID OF SILKWORM, Bombyx mori L.(University of Agricultural Sciences GKVK, Bangalore, 2014-08-08) VASUDHA PRABHAKAR, K.; NARAYANASWAMY, T. K.The investigations on the “Induction of male sterility in silkworm uzi fly, Exorista bombycis (Louis) - A parasitoid of silkworm, Bombyx mori L.” was carried out during 2011-2014 at the Department of Sericulture, University of Agricultural Sciences, GKVK in collaboration with National Center for Biological Sciences, Bangalore for gamma irradiation. The highest uzi fly emergence (89.79%), mating duration (1.56hr) and mating percentage (88.56 %) was recorded in male flies emerged from 8 day old irradiated pupae at 2kr compared to other treated batches. Whereas, the normal female flies mated with sterile males emerged from 8 day old irradiated pupae at 2kr recorded maximum preovipositional period (32hr) and fecundity (510). The maximum time taken for sclerotization (70, 65 and 63.54 min.) by male flies that emerged from 3 day old irradiated pupae at 1, 1.5 and 2kr respectively as compared to control. The minimum ovipositional period (3days), number of fertile eggs (110) and hatching percentage (24.81%) was recorded in normal females mated with sterile males emerged from 8 day old irradiated pupae at 2kr. Studies on field release of sterile male flies near rearing houses resulted in decreased hatching percentage (17.38%) compared to un released village. Mass production of uzi maggots in-vitro revealed that 2 mated females provided with 300 worms for oviposition resulted in maximum fecundity (657), maggots formed (562), pupae formed (544), flies emerged (534), male pupal weight (1.26 g), female pupal weight (0.96/g), male pupal length (0.91cm) and female pupal length (0.97cm) compared to 50 , 100 and 200 silkworms provided batches.