Seed germination and plant management
In 2018, the 300 seeds from GM and wild soybean samples were grouped
into three replicates, and three replicates of 100 seeds each and all 54
F1 seeds were then placed individually in a 12-well cell
culture plate (Corning Costar, New York, USA) with two layers of filter
paper. Finally, 400 μL sterile distilled water was added to each well,
and plates were kept in climate chambers (Binder model KBF 720,
Tuttlingen, Germany) under 55% RH, 25 ± 2 °C and continuous dark
conditions for 21 days. The number of germinated seeds per day was
recorded (i.e., radicle protrusion > 5 mm) and was
expressed as a percentage of the total number of tested seeds
(germination percentage). The germinated seeds were removed immediately
once they were counted to prevent any counting errors. Germination
experiments of GM soybean, wild soybean, hybrid F2 and
hybrid F3 seeds were carried out under the same
experimental conditions in 2019 and 2020.
The germinated seeds were each transplanted and grown in a plastic pot
(730 mm × 560 mm × 230 mm) filled with mixed soil containing farmland
soil and soil composite (25% peat, 25% compost, 25% perlite, 25%
vermiculite) at a ratio of 1:1. A bamboo pole (diameter of 1.5 cm and
height of 230 cm) was inserted into the pot and carefully fixed to allow
for plant climbing. During the plant growing season, weeds were manually
removed from cultivation pots, and agricultural agents such as plant
growth regulators, insecticides, and fertilizers were not applied.