Why would seeds dropped near their parent plant not germinate?
Insufficient space
Insufficient water
Insufficient nutrients
The limited space around the plant will have a limited amount of water and nutrients in the soil, which may be enough for only a few seeds. The majority of seeds will be deprived of enough nutrition to germinate and will never germinate or die in their infancy. Sunlight plays no role in the germination of seeds. So excess sunlight does not prevent the germination of seeds.