Effects of excessive soil moisture at different growth stages on seed yield of summer buckwheat.

摘要

Buckwheat cv. Kitawasesoba plants grown in pots were exposed to waterlogging (water table 5-7 cm below the soil surface) or flooding (water table 2-3 cm above the soil surface) for different periods at the first leaf, flowering or ripening stage (5,18 and 31 days after emergence, respectively). The earlier the developmental stage at treatment and the longer the treatment, the more severe the effects of excessive soil moisture on seed yield. When plants were waterlogged at the first leaf or flowering stage for 3 days or at the ripening stage for 6 days, the seed yield decreased <10%. However, it decreased significantly when the treatment period was prolonged. When the plants were flooded for 1 day at the first leaf stage or for >3 days at the flowering or ripening stage, seed yield decreased significantly. Seed yield was reduced by waterlogging and flooding at the first leaf and flowering stages mainly because of a low number of seeds due to a reduction in the number of flowers per branch. The decrease in seed yield caused by flooding at the flowering and ripening stages for more than 10 and 3 days, respectively, was significantly correlated with the decrease in 1000-seed weight. Seed setting ratio was not decreased by excessive soil moisture.