Expression and inheritance of tolerance to waterlogging stress in wheat

Approximately 10 million hectares of wheat (Triticum aestivum L.) globally experience medium to serious waterlogging. The inheritance of waterlogging tolerance was determined in reciprocal crosses of three tolerant (Prl/Sara, Ducula and Vee/Myna), and two sensitive (Seri-82 and Kite/Glen) spring bread wheat lines. Parents, F1, F2, F3, and backcross generations were studied under field conditions in Cd. Obregon, State of Sonora, Mexico. Flooding was applied when plants were at the three-leaf and first-internode stages. Basins were drained after 40 days of flooding. Leaf chlorosis was used as a measure of waterlogging tolerance. The sensitive by sensitive cross, Seri-82 x Kite/Glen, showed the highest mean values for percentage leaf chlorosis and area under chlorosis progress curve (AUCPC), and the lowest mean values for plant height, biomass, grain yield, and kernel weight. The F3 of the cross between the two tolerant parents Ducula and Vee/Myna had the lowest mean values for percentage leaf chlorosis and AUCPC, and the highest mean values for plant height, biomass, and grain yield. The expression of waterlogging tolerance was not influenced by a maternal effect. The F1 hybrids were intermediate for leaf chlorosis, indicating that tolerance was additive. Quantitative analysis also indicated that additive gene effects mainly controlled waterlogging tolerance in these crosses. Segregation ratios of F3 lines indicated that up to four genes controlled waterlogging tolerance in these crosses, with two genes adequate to provide significant tolerance. Early-generation selection for tolerance would be effective in these populations.