Unveiling trait synergies in novel Bt cotton hybrids for optimized yield and superior fiber quality improvement

Cotton ( Gossypium hirsutum L.) is a major fiber and cash crop widely cultivated in tropical and subtropical regions, playing a vital role in Indian agriculture and industry, particularly Bt cotton. Enhancing yield and fiber quality simultaneously is a complex breeding challenge due to trait interrelationships. This study evaluated eight Bt cotton hybrids and two checks for 16 agronomic, yield, and fiber quality traits to identify superior genotypes and understand trait associations. Significant genetic variability was observed across all traits. Seed cotton yield showed strong positive correlations with boll weight ( r = 0.81), number of bolls per plant ( r = 0.91), and lint yield ( r = 0.98). Fiber traits generally correlated positively except for Micronaire, while negative correlations included plant height with uniformity index ( r = −0.79) and uniformity index with lint yield ( r = −0.68). Multivariate PCA clustered hybrids, highlighting UBT 4's superiority for yield-related traits and UBT 6's distinct cluster for high fiber quality traits such as staple length, fiber strength, elongation rate, and uniformity index. Hierarchical clustering validated these groupings, placing UBT 4 and UBT 2 alongside high-yield checks, while UBT 6 was genetically divergent, allowing targeted fiber trait improvement without yield penalties. Six hybrids showed excellent Micronaire values (3.7– 4.2), with UBT 6 excelling in fiber strength and uniformity index. All hybrids demonstrated elongation ratio >7.5%, indicating effective parent selection for fiber quality. This study demonstrates that strategic hybridization can effectively address traditional trade-offs between yield and fiber quality, offering valuable insights for cotton breeding programs.