Effect of Maternal Genotype on Chromosomal Introgression in Lilium (Liliaceae) Hybrids from Parents Producing Aneuploid Female and Male Gametes (AAA × LAAA and LAA × LAAA)

Interspecific hybridization is a key strategy for germplasm innovation in lilies (Lilium spp., Liliaceae). However, successful hybridization between aneuploid female and aneuploid male gametes has not been reported in this genus. We used two triploid female parents—autotriploid (AAA) and allotriploid (LAA)—crossed with an odd-allotetraploid (LAAA) male that produces functional aneuploid pollen—to explore the effects of maternal genotype on chromosome introgression. Genomic in situ hybridization (GISH) analysis was performed on mitotic metaphase chromosomes of the progeny to determine chromosome number and genome composition. Both crosses were successful, confirming aneuploid female × aneuploid male compatibility. The AAA × LAAA progeny had concentrated chromosome numbers (40–45), averaging 2.33 Longiflorum (L) chromosomes, with L and L/A recombinants accounting for 6.67–20%. In contrast, the LAA × LAAA progeny showed wider variation (38–61), averaging 10.67 L chromosomes, with L and L/A proportions of 25.00–39.53%. Therefore, the maternal genotype decisively affects introgression: LAA (containing the L genome) promotes high-proportion alien introgression, whereas AAA (lacking L) favors low-proportion introgression. This is the first report on maternal regulation in aneuploid × aneuploid crosses, providing a theoretical basis for targeted parental selection in lily germplasm introgression breeding.