Assessment of genetic diversity among okra genotypes through PCA and correlation analysis for fruit tenderness, and morphological and yield traits

Most of the local okra varieties grown in Pakistan are prone to several challenges like long maturity periods yet short harvesting time, biotic and abiotic stress, inferior quality and low yield in comparison to countries like India, Nigeria and Iraq. Therefore, this study was designed to measure diversity in available okra germplasm comprising of twenty four genotypes for morphological, yield and quality related traits. Considerable variation was observed for all studied traits except for internodal length, fruit girth, days to fruit maturity and vitamin C. Highest variation was recorded for plant height, leaves plant -1, leaf area, days to flowering, number of fruits plant -1, fruiting span, fruit yield plant -1 and fruit tenderness at 10th and 12th day from flower opening. Plant height was significantly positively correlated with all measured traits except days to flowering, days to fruit maturity and fruit tenderness. Days to flowering were significantly positively correlated with fruit weight and tenderness of at all intervals of picking. Moreover, number of fruits plant -1 was positively correlated with average fruit weight and both were significantly correlated with fruit weight plant -1, fruiting span, protein contents and vitamin C. However, fruit weight plant -1 was significantly positive correlated with fruiting span, but negatively correlated with fruit tenderness. Principal component analysis (PCA) unveiled that PC -I and PC -II had Eigen values greater than one and these two contributed 80.82% of total variability for various traits, but PC -III to PC -VI had Eigen value 0.68, 0.62, 0.58 and 0.39, respectively. Among the three clusters of all genotypes, highest yield and related traits were perceived in cluster I and III, while lowest values of these parameters were recorded in cluster II. Moreover, highest genetic divergence was noticed among cluster I and cluster II. As a result, it is recommended that genotypes residing in I and III clusters can be crossed to assess heterosis for okra yield and quality traits like fruit tenderness.