Assessment of genetic variation against CLCuD in introduced USDA cotton germplasm

摘要

In present study 68 cotton genotypes imported from USA were evaluated for cotton leaf curl virus disease tolerance, monopodia per plant, sympodia per plant, plant height and number of bolls per plant. For evaluation of these traits cluster analysis was employed to obtain suitable parents that can be further used in future breeding programmes for CLCuD tolerance. In addition to these, analysis frequency distribution was also generated to summarise the results on the basis of CLCuD tolerance percentage. For cluster analysis the genotypes were grouped into three clusters (cluster I, II and III) comprised of genotypes with different morphological characters. Cluster II was characterized by genotypes having less attack of CLCuD. Cluster I was represented by genotypes having good plant height and sympodia per plant. Cluster III was characterized by genotypes having high attack of CLCuD, therefore not recommended against CLCuD. Cluster II genotypes are good for CLCuD tolerance and can be utilized in breeding programmes for better CLCuD tolerance. The lowest virus percentage was recorded on the accessions USG16_3098, USG16_3123 and USG16_3089, while the highest virus percentage was recorded on the accessions USG16_3083, USG16_3080 and USG16_3085 as shown by frequency distribution graph. So, it is concluded that the genotypes with lowest CLCuD percentage might be used in breeding programme for the development of CLCuD tolerant varieties