Growth and yield responses of UK wheat cultivars to winter waterlogging

Abstract

SUMMARYWinter waterlogging is expected to become an increasingly serious problem due to climate change. It is therefore important to find whether differences in tolerance to waterlogging exist between wheat cultivars grown in the UK. Screening experiments were conducted outdoors and in a glasshouse to investigate the yield response to waterlogging and waterlogging tolerance at the seedling stage. The experiments suggested that differences in tolerance existed between cultivars, in the form of digression of some cultivars from their expected yield in the outdoor experiment and a significant interaction between cultivar and waterlogging for shoot and root dry weight in the seedling experiment. Cultivars that appeared to differ in their responses to waterlogging were further tested in a field experiment over two seasons and in a second glasshouse seedling experiment. However, there was no significant relationship between measurements taken at the seedling stage and grain yield at maturity; also the field experiment did not provide compelling evidence of differences in tolerance. Cultivars with the largest yield suffered the largest decrease due to waterlogging, and the yield of the cultivar with the lowest yield potential was unaffected. All cultivars showed considerable ability to compensate for winter waterlogging damage by vigorous spring growth. All cultivars produced nodal roots in response to waterlogging, and these displayed evidence of aerenchyma tissue by penetrating below the water level, but no cultivar was any better in this respect than any other. The results of these experiments suggest that screening for waterlogging tolerance at the seedling stage is not representative of final yield. It is suggested that the lack of diversity for tolerance is a result of the inbred nature of UK wheat cultivars and that the overall good level of tolerance and ability to compensate has been selected for, either inadvertently, or as a result of selecting the best cultivars in UK conditions, where tolerance to waterlogging is a part of the general winter hardiness required.