Study On The Potential Of Allotriploid Lilies (Lilium) In Breeding

Lily, belonging to the genus Lilium, is an important bulb flower. It is in the fourth place of the top ten cut flowers in the Netherlands and in the first place in China. Although there are many wild species of Lilium in China, lily breeding lags far behind the Netherlands. We have to import a huge amount of lily bulbs from the Netherlands in recent years. It is very important to breed our own cultivars to get rid of such situation. The common ways of lily breeding are to cross current lily cultivars and cross cultivars with wild species.Allotriploid lily cultivars can be obtained through somatic doubling or sexual polyploidization. Studys on breeding involving allotriploid lily cultivars indicate that, despite the sterility which caused by abnormal meiosis, they can be used as female to cross with appropriate male. In this study, we cross LAA lilies with diploid/tetraploid Asiatic lilies. The following are the results:1. The three LAA lilies ('Brindis','Courier','Pavia') and the two triploid Asiatic lilies ('Navona','Tresor') are sterile. The four diploid Asiatic lilies ('Eleganza','Monte Negro','Renoir','Pollyanna') and the two tetraploid lilies ('Brunello','Val di Sole')are male fertile.2. All LAA x AA crosses were successful with A26 as the pollen donor.56 seedlings were obtained from LAA×A26; all combinations of LAA×AAAA were successful, totally,463 seedlings were obtained. The results indicate that, despite their sterility, the allotriploid lilies can be used as female to cross with appropriate male.3. The GISH analysis of 09LA002 and progenies showed,'Courier'is allotriploid with twelve Longiflorum chromosomes and twenty-four Asiatic chromosomes and no recombinant chromosomes. The chromosome numbers of the seedlings of 090059 are from 24 to 29, six of eight analyzed seedlings carry recombinant chromosomes. The chromosome numbers of the seedlings of 090016 are from 38 to 62, ten of eleven analyzed seedlings carry recombinant chromosomes. Most of the eggs produced by'Courier'are aneuploid, containing intergenomic recombinant chromosomes. It means that allotriploid lilies are not only fertile but will also bring various variations to their progenies, which is a valuable aspect in lily cultivar selection.4. The GISH analysis on the genome composition of functional eggs of LAA x AA/AAAA showed, all of the functional eggs of LAA x AA carry approximate twelve Asiatic lily chromosomes meanwhile most of the functional eggs of LAA×AAAA carry approximate twenty-four Asiatic lily chromosomes. The results indicate that the chances of embryo development are improved when the A-genome chromosome numbers of female gametes are near to that of male gametes.To sum up, although allotriploid lilies are sterile, they can be used as female to cross with appropriate male lilies; the aneuploid eggs they produced and the recombinant chromosomes have high potential in introgression breeding.