Root system

• Primary root system :  It forms at the time of seed germination from embryo and absorbs nutrients for the young seedlings.  These are later replaced by the more permanent secondary root system.
• Secondary root system : It arises at a point above the primary root system as the principal organ of absorption as the young wheat seedling progresses to maturity.  It is the root system which arises from underground nodes at the time of crown root initiation stage (usually 21-25 days after sowing in Mexican dwarf wheat).