The characteristics of abnormal meiosis and functional aneuploid pollen of odd-allotetraploid lily ‘Honesty’ unveiled using in situ hybridization

•Odd-allotetraploid, Lilium ‘Honesty’, has one set of Longiflorum chromosomes and three sets of Asiatic chromosomes.•In its meiosis, both the associated chromosomes (i.e., bivalents or multivalents), and the un-associated ones (i.e., univalents) disjoined at anaphase I.•Its functional pollen grains had the similar sizes though their chromosome numbers were quite variable.•Fritillaria-type embryo sacs are more favorable to aneuploid embryos than Polygonum-type embryo sacs. Odd-allotetraploid lilies, like LAAA, have abnormal meiosis, but there are few reports on the characteristics of their chromosomal behavior and functional pollen. This study analyzed an odd-allotetraploid lily, ‘Honesty’ (LAAA), for its microsporogenesis and functional aneuploid pollen grains using cytogenetic methods together with hybridization. Its microsporogenesis showed that, (1) the homo(eo)logous chromosomal synapsis is quite complex at the metaphase I, in which not only trivalents, but also bivalents, univalents and other various multivalents were found as well, and near all of them could disjoin and move evenly to the opposite poles at the anaphase I; (2) the variation of chromosome numbers of aneuploid pollen occurred mainly at anaphase II because the chromatids of univalents which were divided at anaphase I moved randomly to either of the two poles at anaphase II. Pollen germination and GISH analysis on their progenies, which were obtained from the hybridization between tetraploid Asiatic lily (AAAA) and LAAA, indicated that the functional pollen grains had the similar size of their diameters while their chromosome numbers varied from 15 to 35. The previous and present results show that Fritillaria-type embryo sacs are more favorable to aneuploid embryos than Polygonum-type embryo sacs.