2004 Volume 73 Issue 3 Pages 323-329
Dry seeds of nine soybean cultivars were soaked in water for 48 hours and the effects of the soaking (flooding stress) on plant growth were studied in relation to initial seed moisture content. Both seedling emergence and subsequent growth were suppressed by the soaking. Among the cultivars tested, only Peking was hardly damaged by the soaking showing flooding-tolerance, and the others were injured severely. Sensitivity to flooding stress was greatly influenced by the initial seed moisture content. Soaking 6.5%-moisture seeds in water resulted in a marked reduction in dry matter accumulation in emerged seedlings to 0.5 to 54% of that in the non-soaked control. However, seeds with a high moisture content were less sensitive to flooding. In the seeds containing 14.5% moisture were soaked in water the dry matter accumulation in the emerged seedlings was 65 to 97% of that in the non-soaked control. The protective effect of increasing initial seed moisture on flooding stress was observed in all cultivars although the effect varied with the cultivar. In a field experiment under excessive soil-moisture conditions also, suppression of seedling emergence by flooding stress was alleviated by using seeds with a high moisture content although the effect of using seeds with a high moisture content in reducing flooding injury was less compared with that in the laboratory experiments. Planting of seeds with a high moisture content may be a practical method of reducing the loss in soybean production caused by flooding during the seed-germination period.
