Cluster analysis and genetic variability of sweet sorghum (Sorghum bicolor L. Moench) genotypes using agro-morphological and juice quality traits

Abstract

The present investigation was conducted at Giza Research Station, Egypt, to evaluate the mean performance of 30 sweet sorghum genotypes for stalk and juice yields during the 2021 and 2022 summer seasons. The experiment was laid out as a randomized complete block design with three replicates. The magnitude of genetic variability was estimated using broad sense heritability and genetic advance expressed as a percent of the grand mean. Also, cluster analysis was automated to identify the similarity and dissimilarities among the tested genotypes. The genotype by trait (GxT) biplot was graphically diagrammed to compare genotypes on the basis of multiple traits. Results revealed significant differences among sweet sorghum genotypes for all studied traits across the two seasons. There were three promise genotypes Willy, William, and Atlas that surpassed the other genotypes regarding juice extraction percentage and juice yield indicating their magnitude as breeding materials that may be successfully used in breeding programs of sweet sorghum. The highest genotypic and phenotypic coefficient of variation was recorded by leaf area index, stalk diameter, stalk length, juice extraction percentage, and juice yield. In the same context, high values of heritability accompanied by genetic advance percentage were observed in terms of leaf area index, stalk diameter, stalk length, and juice yield indicating that these traits were well heritable and can be improved through breeding programs. The results of cluster analysis exhibited the presence of considerable genetic diversity among the tested genotypes. Cluster analysis classified the sweet sorghum genotypes into five clusters where the 1 st cluster consisted of four genotypes Willy, William, Rio, and Dall that were lately flowered but recorded the highest values of all studied traits except stalk length, sucrose percentage, and purity percentage giving considerable stalk and juice yields. According to the GxT biplot graph, it is clear that genotypes; William, Rio, Tracy, and Atlas recorded the best values in the case of juice extraction percentage, juice yield, stripped stalk yield, stalk diameter, days to 50% flowering, and leaf area index. Information obtained from this research may be helpful to select the best sorghum genotypes to share in breeding programs to improve the characteristics of stalk and juice yields.