FCM, SSR and CAPS analysis of intergeneric somatic hybrid plants between Changshou kumquat and Dancy tangerine

Flow cytometry (FCM), simple sequence repeats (SSR) and cleaved amplified polymorphic sequence (CAPS) were used to characterize the ploidy level and the nuclear and cytoplasmic compositions of two intergeneric somatic hybrids of Changshou kumquat (Fortunella obovata), leaf parent, and Dancy tangerine (Citrus reticulata), suspension parent. FCM showed that both somatic hybrids were tetraploids. One out of two SSR primer pairs was able to detect polymorphisms between the fusion parents, and the somatic hybrids showed additive banding profiles, showing them to be allotetraploid hybrids with inherited nuclear DNA from both parents. CAPS showed that 4 and 1 polymorphic loci were obtained for parental chloroplast and mitochondrial genomes, respectively. The somatic hybrid plants had the same banding patterns as the suspension parent for all of the polymorphic chloroplast markers, and their mitochondrial banding patterns approximated those of the suspension parent with loss of some mtDNA fragments. The present research plays a pivotal role in understanding the relationship between nuclear and cytoplasmic compositions and the likely field performance of somatic hybrids in the future.