Pod dehiscence in relation to pod position and moisture content in soybean

The relationship between pod dehiscence and the position and moisture content of pods was examined in two soybean cultivars, Fukuyutaka and Keito-daizu. The frequency of pod dehiscence at different parts of the stem was assessed by the strain-gauge method. Pods of the two cultivars were classified into indehiscent, dehiscent (dehisced by the strain-gauge method) and naturally dehiscent pods. The moisture content of pods was measured after drying in a hot-air oven at 105 +/- 1 degrees C for 24 hrs. In both Fukuyutaka and Keito-daizu, the pods at maturity were not dehisced at any part of the stem due to the high moisture content of pods. After maturity, the frequency of pod dehiscence at the upper part of the stem increased as the moisture content of pods decreased in both Fukuyutaka and Keito-daizu. A similar tendency was observed in both the field and the pot experiments. The frequency of pod dehiscence was higher at the upper part of the stem and increased as the moisture content of pods decreased.