Morphological Variability and Taxonomic Relationship of Sorghum bicolor (L.) Moench Accessions Based on Qualitative Characters

Sorghum bicolor (L.) Moench is a member of Poaceae family with three agronomic types corresponds to their specific uses namely grain sorghum, sweet sorghum, and forage sorghum. Although sorghum in Indonesia is considered as under-utilized crop, but it has the potential as an alternative resource for staple food in diversification program to support food security. The potential of sorghum as alternative staple food is due to its high nutritional value, and the ability to grow well in marginal lands with maintaining good productivity. The objectives of this study were to assess the extent of morphological variability and to resolve taxonomic relationship of sorghum accessions from Java Island based on morphological characters. Twenty nine sorghum samples were collected from three provinces in Java, namely Central Java, Special Province of Yogyakarta, and East Java. Morphological data observed refers to Descriptors for Sorghum, generating 19 qualitative characters used in cluster analysis and principal component analysis. Cluster analysis resulted in the grouping of 29 accessions into three groups corresponding to the racial classification of sorghum. Results of principal component analysis showed that the main distinguishing characters between groups were inflorescence compactness and shape, glume coverage, presence or absence of awn, presence or absence of grain sub-coat, grain shape, and grain color. Analysis of correlation showed that there were very strong relationship between glume coverage and the presence of awn, and between the presence of grain sub-coat and grain color. Results of this study revealed that sorghum accessions cultivated on Java Island consisted of four races namely Bicolor, Guinea, Caudatum, and Kafir.