Diversity and correlation studies of intraspecific hybrids for their morphological traits in cotton (Gossypium hirsutum L.)

Abstract The cotton (Gossypium hirsutum L.) is great source of natural fiber and sixth largest source for oil and contributed to GDP of Pakistan. Therefore, present research aimed to assess the genetic diversity of 61 crosses in terms of yield and yield-related traits. This study also analyzed the correlation between these traits for selection. Plant height showed a positive and highly significant correlation with the main stem nodes. However, the number of squares showed a positive and highly significant relationship with plant height and number of main stem nodes. The number of flowers showed a moderate and significant correlation with the number of squares. Furthermore, the number of green bolls strongly correlated with the number of main stem nodes, plant height and number of open bolls. The cotton leaf curl virus disease % was negatively correlated with the number of main stem nodes plant height and number of green bolls. Genetic diversity among germplasm forms the foundation of any breeding program and is pivotal for increasing yield. Principal component analysis revealed a total variance of 53% among crosses, with PC-I contributing 34.3% and PC-II contributing 18.7% of yield-related traits. Of eight PCs the four PCs exhibit > 1 eigen values. The number of squares per plant, the number of green bolls, and the number of flowers had positive effects on the first two PC components. Clusters I and II exhibited maximum values for the number of squares, the number of green bolls, the number of flowers, and resistance to cotton leaf curl virus disease. Crosses in cluster II displayed reasonable values for the number of open bolls and the number of flowers but showed susceptibility to cotton leaf curl virus disease. The crosses like, IS-29 × VR-5, 217007 × VR-5, IS-12 × VR-5, (MNH-1090 × MNH-875) × 875, (MNH-1090 × MNH-875/4) × 875/4, (MNH-872 × SS 32) × 872, CRP-255 × Super Gold, CRP-212 × FH-333, (MNH-872 × SS-102) × 872, (MNH-872 × MNH-875/4) × 875/4, CRI-288 × CRI-294, and CRI-287 × CRI-212 were genetically diverse for most of the studied morphological traits. This comprehensive information, derived through the application of various statistical tools, is essential for assessing the diversity of crosses to successfully develop an improved breeding program.