TBST-2, A HIGH YIELDING MULTIPLE RESISTANT FCV TOBACCO LINE FOR TRADITIONAL BLACK SOILS OF ANDHRA PRADESH

Abstract

TBST-2 is a high yielding flue-cured Virginia tobacco line developed through interspecific hybridization between Nicotiana gossei, a wild relative of cultivated tobacco and N. tabacum cv. Hema. Wild species, N. gossei was identified as a source for resistance to tobacco aphid, Myzus nicotianae, which is an economically important insect pest on tobacco. With a view to incorporate aphid resistance from N. gossei to susceptible N. tabacum, cv. Hema was crossed with N. gossei and interspecific F1 hybrids were obtained. Fertility was restored in a few segregating progenies through pedigree and back cross breeding and the resulting advanced cross derivatives with restored fertility were screened under artificial inoculation against tobacco aphid. Selections having aphid resistance in addition to normal fertility and desirable agronomic traits were further advanced. Subsequently, the aphid resistant progenies in F9 and different back cross generations, were screened against TMV disease under artificial inoculation. A number of light cast and dark cast, resistant advanced interspecific cross derivatives were evaluated in replicated yield trials at CTRI, Rajahmundry. One among these lines, TBST-2 showed resistance to TMV besides tolerance to tobacco aphid was identified as significantly superior to the ruling traditional black soil varieties for cured leaf yield. In the station trials, TBST-2 showed an increase of 16 & 31% green leaf, 15 & 30% cured leaf, 25 & 27% bright leaf yield and 30 & 28% increase in grade index, respectively over the best check variety, VT 1158. In on-farm trials, TBST-2 with an average cured leaf productivity of 2799 kg/ha recorded more than 13% increase over Siri. In SLS, with an average productivity of 2189 kg/ha cured leaf yield, TBST-2 showed 15% improvement over Siri. The proposed variety TBST-2 showed maximizing yield potential at plant spacing of 70 x 50 cm with 45 kg N/ha. In view of its high yield potential, acceptable physical and chemical quality characteristics, resistance to TMV disease and moderate resistance to tobacco aphids, TBST-2 was identified by the VIII AINPT Group Meeting (2015) and CTRI Institute Research Council for release for commercial cultivation in traditional black soils and southern light soils of Andhra Pradesh.