Expression and inheritance of tolerance to waterlogging stress in wheat

Approximately 10 million hectares of wheat (Triticum aestivum L.) globally experience medium toserious waterlogging. The inheritance of waterloggingtolerance was determined in reciprocal crosses ofthree tolerant (Prl/Sara, Ducula and Vee/Myna), andtwo sensitive (Seri-82 and Kite/Glen) spring breadwheat lines. Parents, F1, F2, F3, and backcrossgenerations were studied under field conditions in Cd.Obregon, State of Sonora, Mexico. Flooding was appliedwhen plants were at the three-leaf and first-internodestages. Basins were drained after 40 days of flooding.Leaf chlorosis was used as a measure of waterloggingtolerance. The sensitive by sensitive cross, Seri-82 × Kite/Glen, showed the highest mean values forpercentage leaf chlorosis and area under chlorosisprogress curve (AUCPC), and the lowest mean values forplant height, biomass, grain yield, and kernel weight.The F3 of the cross between the two tolerant parentsDucula and Vee/Myna had the lowest mean values forpercentage leaf chlorosis and AUCPC, and the highestmean values for plant height, biomass, and grainyield. The expression of waterlogging tolerance wasnot influenced by a maternal effect. The F1 hybridswere intermediate for leaf chlorosis, indicating thattolerance was additive. Quantitative analysis alsoindicated that additive gene effects mainly controlledwaterlogging tolerance in these crosses. Segregationratios of F3 lines indicated that up to four genescontrolled waterlogging tolerance in these crosses,with two genes adequate to provide significanttolerance. Early-generation selection for tolerancewould be effective in these populations.