Advances in Apomixis and Polyembryony Research in Citrus Plants

In apomixis asexual reproduction,the ovule generates embryogenesis without meiosis or fertilization,leading to embryo development and seed formation.Apomicts inherit the mothers genotype entirely,and therefore have unique significance in research and breeding.Polyembryony,in which nucellar embryos develop from nucellar tissue to undergo apomixis,is a unique phenomenon of Citrus and other genera of Rutaceae.This review focused on the phenomenon of adventitious embryony in Citrus and recent progress in histocytology and genetics.Nucellar embryony hinders the formation of hybrid offspring in Citrus,but it can produce offspring with good unity and can also be used for generating virus-free seedlings.