Barley response to waterlogging duration at tillering

Waterlogging can reduce barley grain yield depending on the sensitivity of the cultivar, the duration, and the stage of development in which waterlogging occurs. This study was conducted to determine whether waterlogging during the tillering stage reduces the grain yield of barley by reducing the spikelet formation and, consequently, the number of kernels per spike, and whether this reduction is related to the length of waterlogging. The impacts of seven waterlogging durations of 4, 8, 12, 16, 20, 40, and 60 d, imposed at 3-leaf and 4-leaf stages were investigated for 2 yr at University of Pisa, Italy, on grain yield, grain yield components, straw, and root dry weight and nitrogen concentration of grain, straw, and roots of two cultivars (‘Amorosa’ and ‘Mattina’) of six-row barley (Hordeum vulgare L.). Cultivar Mattina was tolerant to waterlogging and none of the measured parameters were different from the controls. Cultivar Amorosa was sensitive to waterlogging prolonged for more than 16 d. The highest waterlogging duration (60 d) decreased grain yield (-23%), straw (-29%) and root dry weight (-24%), culm number per plant (-36%), and number of spikelets per spike (-21%) and kernels per spike (-23%) of the sensitive cultivar. The stage at which waterlogging was imposed did not affect the measured parameters. High genotypic differences for tolerance to waterlogging exist in barley. In conclusion, the grain loss of the sensitive cultivar Amorosa resulted from the slowing down of spikelet initiation and consequently the reduced number of kernels per spike