Waterlogging affects leaf and tillering dynamics in wheat and barley

Abstract

The aim of this study was to analyse (i) the crop attributes that determine floweringtime (i.e. final leaf number, FLN; and phyllochron, Phy), (ii) the dynamics oftiller appearance and (iii) the synchrony between leaf and tiller appearance inwheat and barley plants exposed to waterlogging. Two experiments were carriedout in pots, in which wheat and barley cultivars were exposed to five waterloggingtreatments, during different periods throughout the crop cycle, from emergenceto maturity. The appearance of leaves and tillers on the main stem was measuredtwice a week in labelled plants. Waterlogging from emergence to flag leaf appearancesignificantly delayed time to flowering. The delay was greater when waterloggingoccurred at the beginning of tillering, lengthening the period fromemergence to flowering 24 % (13?15 days) in barley and 10?15 % (6?10 days)in wheat, as compared to control. Phy was the main attribute explaining the delayin flowering, as FLN was not altered. Waterlogging during the early stages ofdevelopment reduced tiller appearance rate (TAR) in both species, but this effectwas partially counterbalanced by a lengthening of the tillering phase, so the effecton final tiller number at maturity was limited. In conclusion, the exposure ofwheat and barley to waterlogging during early stages of development delayed timeto flowering and reduce TAR in both species. Waterlogging during moreadvanced crop stages produced slight effects on tillering dynamics, which wouldindicate that waterlogging affected structure generation more than mortality