Why can several young embryos form in a gnetophyte seed while only one usually matures?

In gnetophytes, the development of multiple embryos within a single seed is a result of the reproductive process where several pollen tubes may enter the female gametophyte, leading to multiple fertilization events.1

While these multiple young embryos can initiate development, it is typical for only one to reach a fully mature stage within the seed. This phenomenon, known as polyembryony, is also observed in other gymnosperms such as cycads, ginkgo, and conifers, where multiple zygotes may form but only one survives to maturity.12