Chromosomal analysis of Lilium longiflorum x Asiatic hybrids using GISH (genomic in situ hybridization)

Abstract

In Lilium, a popular horticulture crop, the main objective of crossbreeding is introgression of desirable genes and features into new cultivars. Commercial Lilium cultivars were produced primarily through 2n-gametes or 2x-gametes as parental plants or backcrossing. The primary genetic difference in 2 methods, is the presence of genomic recombination. Especially, GISH (genomic in situ hybridization) among molecular cytogenetic analysis, is the relevant technique to detect genetic information; genome composition, chromosome behavior during meiosis and recombination of hybrids as using their parental DNA as a probe. Based on previous studies, in this research, 12 LA (L. longiflorum x L. Asiatic hybrids) hybrids were analyzed by GISH (genomic in situ hybridization) along with ploidy analysis, and pollen germination tests. The LA hybrids used in this study, showed less pollen germination ability (ranged 0 - 21.74%), but germination of ‘Caesars Palace’ was significantly higher (59.09%). Interestingly, ploidy analysis showed that ‘Caesars Palace’ was tetraploid and ‘Batistero’ had one more additional chromosome from the L genome. Nine of the 12 cultivars exhibited recombination and 3 had only non-recombinant chromosomes; fewer L. longiflorum chromosomes were present in the cultivars than Asiatic chromosomes. Consequentially, it is assumed that 2n-gametes were more common methodology than 2x-gametes for producing commercial cultivars. Moreover, backcrossing tended to be performed with the Asiatic hybrid cultivar.