In what type of asexual reproduction are seeds produced even without the joining of sperm and eggs?

This type of asexual reproduction is called apomixis.

Apoximis is reproduction by special generative tissues without fertilization. It includes parthenogenesis in animals, in which the new individuals develop from unfertilized egg, and apogamy in certain plants in which the generative tissues may be the sporophyte or the gametophyte.