This paper focuses on the importance of the genetic diversity and application of statistical tools in the analysis of genetic variation at the interspecific and intra specific level of Bt and non-Bt cotton varieties in Andhra Pradesh. Genetic variation and assessment of distribution of a crop species and its relatives is essential in understanding the pattern of diversity and evolutionary relationship between accessions that help to sample genetic resources in a more systematic fashion for conservation and plant improvement. Currently a number of tools and methods are available for analysis of statistical genetic diversity with qualitative and quantitative traits in between group populations [treated (Bt) and non treated (non-Bt)] and within group individuals (Bt and non-Bt) of Bt and non- Bt elite cotton varieties of Andhra Pradesh.
The present study revealed more significancant mean value for characters like Average yield per plant (Nuziveedu Bt, Tulasi Bt, JK Bt), Boll per plant (Tulasi Bt, Nuzivvedu Bt),Effective monopodias (Kaveri Bt, Tulasi Bt, Bhaskar Bt) and Number of bolls per plant (Tualasi Bt, JK Bt, Vibha Bt) for Bt than the non-Bt varieties (G.hirusutum and G.arboreum). Where as non Bt-varieties have shown significance for the characters like Plant height (Narasimha, NDLH-1959, Srinandi, Vibha non-Bt, Bhaskar non-Bt), Maturity days (G.hirusutum, Yaganti, Vibha nonBt) and Days to flower (NDLH-1938, Yaganti, Tulasi, Bhsakar) respectively. A few of non-Bt varieties like Sivanandi (G.hisutum), NDLH-1938 (G.hisutum), and Yaganti (G.arboreum) have also shown significance in production of yield per plant. Overall the growth parameters were significant in non-Bt than Bt cotton varieties in contrast to the production and yield per plant.
