Identification of waxy genotype in sorghum genetic resources using waxy gene-based markers and iodine staining methods

Sorghum is widely recognized as a versatile crop with significant value in the production of food and energy. Sorghum with waxy trait (low amylose) is more palatable to the food industries and more appealing to consumers than nonwaxy variety. However, waxy sorghum has not yet been introduced to Indonesia, making it difficult to use sorghum to support the government of Indonesia's initiative to diversify the country's main foods. This study aimed at identify the waxy traits in a set of sorghum germplasm collected in Indonesia using waxy gene-based markers and iodine staining screening approaches. A total of 48 (27 introduced and 21 local) sorghum accessions collected in the IAARD gene bank along with 4 national sorghum varieties, which were subjected to both molecular analysis and iodine staining assay. The presence of waxy allele in the sorghum gene bank collection was identified using DNA markers associated with two waxy alleles (wxa and wxc). Iodine staining assay performed in the present study was applied to verify the waxy phenotype in sorghum grain and waxy genotypes in sorghum pollen. Based on molecular analysis and pollen staining, five local sorghum accessions were classified as heterowaxy sorghum. These accessions showed reddish-brown color in their endosperm after treated by iodine staining which confirmed them as waxy phenotype. These findings would be beneficial for further improvement of grain quality in sorghum breeding programs