Exploring Host Resistance and Character Association in Diverse Cotton Germplasm to Manage Cotton Leaf Curl Disease (CLCuD) at Two Hotspots in Punjab, Pakistan

Abstract

Cotton leaf curl disease (CLCuD) caused by Begomoviruses is a significant constraint to cotton production in Pakistan. Breeding for resistance is a key strategy to manage the disease. However, developing varieties with stable resistance and good fiber quality poses a challenge. Therefore, the study aimed to evaluate 71 cotton genotypes, including 67 accessions from Pakistan, three from Turkey and one from India, for resistance to CLCuD and yield traits at two locations (Faisalabad and Vehari) in Punjab. The association between traits was analyzed. A field trial was conducted using a randomized complete block design with three replications. Genotypes were evaluated for CLCuD severity, yield, and fiber traits. Correlation and factor analyses were done. The results showed significant variation among genotypes for CLCuD resistance and other characteristics. Some genotypes like FH-490 and FH-444 showed high yield, fiber length and strength, and tolerance to CLCuD. These could be directly used as parent lines in breeding programs. Furthermore, the factor analyses showed that at CRS, Faisalabad 3 PCs have eigenvalue > 1 with a contribution of 69.86%. However, at CRS, Vehari, these three components contributed 66.98% of the total variation in the cotton genotypes assessed for CLCuD, yield and fibre-related traits. Screening criteria were based on virus tolerance and performance of genotypes concerning superior boll number, sympodial branches and boll weight, and plant height. The study identified promising cotton lines with CLCuD tolerance and production traits. Character associations provide insights for breeding programs to develop cultivars with integrated disease resistance and superior fiber quality.