Cytogenetic assessment of Lilium longiflorum × L. Hansonii revealed by genomic in situ hybridization (GISH)

Martagon (Lilium hansonii; MM) and Longiflorum (LL) are two major groups under the family Liliaceae, used for modern breeding to introduce new inter-genomic lily cultivars. Interspecific F₁ hybrids (LM) introduced through cut-style method between two diploid Lilium longiflorum (2n=2x=24) and Lilium hansonii (2n=2x=24) were evaluated cytogenetically by genomic in situ hybridization (GISH) technique. However, GISH analysis of F₁ interspecific (LM) hybrids showed equal chromosomal contribution from both female Lilium longiflorum (LL) and male Lilium hansonii (MM). Each of the parent contributed 12 chromosomes except three crosses i.e., two of L. longiflorum ‘White Tower’ × L. hansonii; (2x-1) and one of L. longiflorum ‘Bright Tower’ × L. hansonii; (2x-1). Among 11 inter-genomic crosses, 3 crosses failed (False hybrid) and 8 crosses (True hybrids) showed different ploidy level i.e., 2n=2x=24, 2n=2x-1=23 and 2n=2x-1=23 respectively. Recombinant chromosome usually not found in F₁ interspecific lily hybrids. Most often, genomic recombination occurred in the cross between two genetically different parents. Chromosome pairing and crossing over normally occurred during meiosis in backcross progenies. However, in this study, genome analysis (GISH) of F₁ hybrids (L. longiflorum ‘White Tower’ × L. hansonii) showed four recombinant sites including two M/L and two L/M recombinant chromosomes that denotes high genetic relationship between L. longiflorum and L. hansonii.