Special Behavior of Homo(eo)logous Chromosomes at Meiosis and the Mechanism of Partial Female Fertility of Allotriploid Lilium ‘triumphator’ (LLO)  

Abstract

Background: The abnormal meiosis of triploid is paid little attention; however, triploid not only is an important trend of ornamental breeding but also is regarded as a bridge of plant polyploidy speciation. In the present research, an allotriploid lily ‘Triumphator’ (LLO, 2n = 3x = 36 ) was investigated. Results: The results showed that the homoeologous chromosomes of two L-genomes formed bivalents and then disjoined and their half-bivalents moved to opposite poles at anaphase I; The chromosomes of O-genome formed univalents, among which, some attached to spindle fibers on two sides, their sister chromtids moved to the opposite poles slower than half-bivalents; some attached to spindle fibers on one side, they move to one pole at similar speed to half-bivalents; some of which deattached to spindle fibers at kinechores on either side, they became micronuclei at anaphase I. Conclusions: Interploid hybridizaitons showed that the LLO lily, regarless of male sterile, could be female parents to crossed with appropriate males to produce aneuploids, supporting the hypothesis -- five same genomes is essential for its endosperm development in interploid hybridizations of Lilium. The discussion well not only explained why triploid lilies with Fritillaria embryo sacs, regardless of male sterile, are usually partial female fertile while other plants with polygonum embryo sacs are seedless; but also explained that why 3x × 2x/4x lilies and tulips produce predominantly aneuploids while 3x × 2x/4x and 2x/4x × 3x of other plants, including 2x/4x × 3x of lilies and tulips, produce euploids and near so.