Deletion commonly found in Waxy gene of Japanese and Korean cultivars of Job's tears (Coix lacryma-jobi L.)

We isolated the entire sequence of the coding region of Waxy gene of a non-waxy accession of Job's tears (Coix lacryma-jobi) by PCR-based methods. We also compared the entire sequences of the gene between two non-waxy accessions and three waxy cultivars and found a 275-bp deletion in the coding region (exons 10-11) of this gene specific to waxy cultivars. We showed by PCR genotyping that this deletion is commonly found in Japanese and Korean cultivars and confirmed that this deletion resulted in lack of Wx protein. We also confirmed that this polymorphism of the gene co-segregates with phenotypes in endosperm and pollen. These results suggest that this PCR-based marker will be useful in breeding of Job's tears and that genetic information obtained in other grass species will be also useful in genetics and breeding of Job's tears.