GENETIC ARCHITECTURE, HETEROSIS AND COMBINING ABILITY IN SILKWORM, Bombyx mori L.
| dc.contributor.advisor | NARAYANASWAMY, T. K. | |
| dc.contributor.author | ASHOKA, J. | |
| dc.date.accessioned | 2017-03-01T09:14:37Z | |
| dc.date.available | 2017-03-01T09:14:37Z | |
| dc.date.issued | 2009-09-15 | |
| dc.description.abstract | 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. | en_US |
| dc.identifier.other | Th-9499 | |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810003378 | |
| dc.language.iso | en | en_US |
| dc.pages | 312 | en_US |
| dc.publisher | University of Agricultural Sciences GKVK, Bangalore | en_US |
| dc.sub | Sericulture | en_US |
| dc.subject | null | en_US |
| dc.theme | SILKWORM | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | GENETIC ARCHITECTURE, HETEROSIS AND COMBINING ABILITY IN SILKWORM, Bombyx mori L. | en_US |
| dc.type | Thesis | en_US |