Revealing the abnormal meiosis and the variation of the functional female gametes of aneuploid lily (Lilium) using genomic in situ hybridization (GISH)

Abstract

Abstract Aneuploid lilies (Lilium) could be obtained from the LAA/LAAA × AA/AAAA hybridization; however, the characteristics of their meiosis and fertility has not been reported. In this study, an aneuploid lily, J1614, was extensively investigated for its microsporogenesis, fertility and functional eggs using conventional and modern cytogenetic methods. The results indicated that J1614 was an aneuploid Longiflorum-Asiatic (LA) lily (2n = 48 = 7L + 39A + 2L/A) while ‘Pearl Jason’ was an autotetraploid Asiatic lily (2n = 48A); L-chromosomes of J1614 usually formed univalent while A-chromosomes associated not only predominantly trivalents, but also tetravalents, bivalents, and even univalent at metaphase I as well; clearly, both univalents and other associated chromosomes were separated and moved to opposite poles at anaphase I; besides, lagging chromosomes and micronuclei were observed during microsporogenesis. Hybridization showed that J1614, regardless of its male sterility, had better partial female fertility when tetraploid a lily was used as male than when a diploid as male. The nine seedlings of J1614 × AAAA were all aneuploid with variable total chromosomes ranging from 46 to 53, meaning that the functional eggs produced by J1614 contained variable chromosomes ranging from 22 to 29. Based on the present results, we concluded that once good lines are selected from aneuploid lilies, they may not only become cultivars through vegetative propagation, but also become parents to breed new aneuploids and realize introgression breeding. In addition, the mechanism of abnormal meiosis of aneuploid lilies was hypothesized.