Starch and WSP contents. Soluble glucan polymer (WSP) and insoluble starch granules were isolated from endosperm tissue of single kernels harvested 20 DAP. The quantities of each polymer were determined and normalized to endosperm tissue dry weight (DW). se values are indicated. The numbers of single kernels analyzed for each genotype were as follows: W64A, parent plants (p) = 12, individual kernels (n) = 48; du1-R4059, p = 4, n = 14; du1-Ref, p = 5, n = 19; isa2-339, p = 3, n = 10; du1-R4059, isa2-339, p = 5, n = 30; du1-Ref, isa2-339, p = 3, n = 20. The full data set is shown in Supplemental Table S1. Differences from the wild type are all statistically significant (P < 0.0001) with the exception of WSP content in du1-Ref, du1-R4059, and isa2-339 single mutants.