Verification of QTL controlling root aerenchyma formation in a maize x teosinte Zea nicaraguensis advanced backcross population

Root aerenchyma formation is considered to be one of the most important characteristics for adapting to flooding. Using an F-2 population of maize B64 x teosinte Zea nicaraguensis, we earlier found that, in Z. nicaraguensis, quantitative trait loci (QTLs) in two regions of chromosome 1 (Qaer1.02-3 and Qaer1.07) are associated with aerenchyma formation under non-flooding conditions. The objective of this study was to determine the utility of these (and any other) aerenchyma QTLs in marker-assisted maize breeding. For this study, an elite maize Mi29 x teosinte Z. nicaraguensis 214 BC2F1 individual population was used for advanced backcross-QTL mapping (AB-QTL). An SSR-based map was constructed using 94 markers, covering 852.7 cM for the ten chromosomes. Mapping revealed that a QTL for aerenchyma formation under non-flooding conditions exhibiting a larger effect was located on chromosome 1 (bin 1.06), the position of which was close to the previously identified Qaer1.07. Also, two QTLs with minor effects were mapped to a different position on chromosomes 1 (bin 1.11) and 5 (bin 5.09). With a few additional backcrosses, it will be possible to obtain near-isogenic lines possessing aerenchyma-forming genes. These materials may be useful in breeding flooding-tolerant maize hybrids.