Variations in apomixis in diploid Paspalum rufum

The genus Paspalum (Poaceae) is a model to study gametophytic apomixis and its strong relation with polyploidy. Delgado et al. analyse the reproductive behaviour of natural diploid individuals of P. rufum and find that under self-pollination induction three genotypes develop seeds from both meiotic and aposporous embryo sacs, and one of them is able to complete the apomictic pathway. Cytoembryological observations reveal that all genotypes form aposporous embryo sacs, suggesting that apospory and parthenogenesis might be uncoupled. These results demonstrate variation in the functionality of apomixis components and also that genetic determinants of apomixis are not sufficient for an appreciable expression of the trait at the diploid level.