Polyembryony in the interspecific hybrids between apricot and almond

Seed polyembryony, referring to as the phenomenon that multiple embryos existed in the same seed coat, widely occurred in such fruit crops as mango, citrus and Fragaria species and so on. It is a useful trait in breeding and propagation of them. However, polyembryony has not previously been reported in apricot (Prunus armeniaca) until we recently obtained the interspecific hybrids between apricot and almond (P. amygdalus). The apricot we crossed in the distant hybridization was kernel-using apricot, a special apricot germplasm resource native to north China with thin, little juicy, astringent flesh but large-size sweet kernel within the stone. The objective of the interspecific hybridization program was to widen the genetic basis of the kernel-using apricot cultivars by the introduction of valuable genes from almond. Among the hybrids, we found that some specific individuals had seeds with multiple embryos. And such individuals showed different frequencies of polyembryony (FP) ranged from 3.3 to 40%. The hybrids numbered ‘P26-99’, which obtained by the cross between P. armeniaca ‘Longwangmao’ and P. amygdalus ‘Italian 1’ had the highest FP of 40%, ‘P56-89’ crossed between ‘Longwangmao’ and P. amygdalus ‘Italian 2’ with FP of 25%, ‘P46-4’ cross between ‘Longwangmao’ and P. amygdalus ‘Nonpareil’ with FP of 6.7% and ‘P7-45’ cross between ‘Longwangmao’ and P. amygdalus ‘Italian 1’ with FP of 3.3%. The plant materials with high FP might have great potential value in apricot breeding program in the future.