Further Mapping and Epistasis Analysis of Two Quantitative Trait Loci of Kernel and Cob Anthocyanin Contents in Maize

In our previous study, two major quantitative trait loci (QTLs) for kernel anthocyanin content in maize (Zea mays L.) were mapped on chromosome 6 and chromosome 10 by using two related F-2:3 populations derived from crosses of 'Mu6' x 'Super Dark Maize' (SDM) and 'Mo17' x SDM. In this study, two sets of near isogenic lines, MuS-BC4F3 and MoS-BC4F3, were developed and used to further map the two QTLs and analyze the epsitasis between the two QTLs. GEN6 was further mapped in the interval S8-umc1105 on chromosome 6 for MuS-BC4F3 and S8 to mmc0523 on chromosome 6 for MoS-BC4F3. GEN10 was further mapped in the interval IDP8526 to S44 on chromosome 10 for MuS-BC4F3 and bnlg1028 to IDP8526 on chromosome 10 for MoS-BC4F3. GEN6 and GEN10 controlled both kernel anthocyanin content and cob anthocyanin content. The epistasis between GEN6 and GEN10 was a coadaptive interaction. The anthocyanin content is likely to greatly increase when GEN6 and GEN10 coexist. Additive x dominant (AD) effects were the largest of all the epistatic effects for kernel anthocyanin content; additive x additive (AA) effects were the largest for cob anthocyanin content. These results could provide a new reference for anthocyanin's genetic mechanism and high anthocyanin breeding in maize.