BSR-seq for mapping a sweet gene in maize

Sweet corn is a specialty maize variety grown for human consumption because of its delicious kernels with high sugar content. We find a new crispy sweet corn germplasm that was not caused by mutations of known sweet genes, such as su1, se1, sh1, and sh2. Genetic analysis indicates that the crispy sweet kernels were controlled by a single recessive gene, cs1. To clone the causal gene, four F2 populations were generated by reciprocally crossing of a crispy sweet hybrid corn and two common corns, Jing724 and Jing2416 (two inbred lines), including cs1 x Jing724, Jing724 x cs1, cs1 x Jing2416 and Jing2416 x cs1. In each F2 population, 30 seedlings of sweet F2 kernels and 30 seedlings of common F2 kernels were pooled into two pools, sweet pool, and wild type pool, respectively, for BSR-seq analysis. The results of four BSR-seq assays show that the causal gene was mapped at the interval of 24-68 Mb on chromosome 10.