Amylose content is a key factor affecting the eating and cooking qualities of rice. In our previous study, protein disulfide isomerase like 1-1 (PDIL1-1) on chromosome 11 was a candidate gene for amylose content (AC) trait. Based on whole genome sequencing, polymorphisms were identified between Dodamssal and Hwayeong on PDIL1-1. In this study, the association of PDIL1-1 on AC was characterized. Haplotype analysis of 79 KNU accessions highlighted the presence of allelic patterns identifiable by the sequence variants between Dodamssal and Hwayeong. Identified SNPs and InDel were used to develop gene-based molecular markers for PDIL1-1. The 29 F₂ plants and 160 Korean japonica cultivars were classified into two and three groups, respectively, based on the G/A SNP at position -4973180 and ATTCG/G at position -4974161. Our findings revealed that the G/A SNP at position -4973180 of PDIL1-1 plays a role in regulating the AC in japonica rice. This suggested that PDIL1-1 would be useful for fine-tuning the rice AC. To our knowledge, no studies of the allelic variation of the PDIL1-1 gene regulating AC have been reported worldwide. Furthermore, no research had reported the development of PDIL1-1 gene-based molecular markers.