Analysis of endosperm development of allotriploid × diploid/tetraploid crosses in Lilium

摘要

Lilium are Fritillaria-type plants. Triploid lilies, regardless of their male sterility, can be used as female parents to cross with appropriate males, in contrast to other triploid Polygonum-type plants, which are usually seedless. Up to now, however, little attention has been paid to the reason. Here we made allotriploid × diploid/tetraploid crosses in Lilium. Endosperm and progenies of LAA × AA/AAAA crosses were analyzed for ploidy level and genome composition. The endosperm of some LAA × AA/AAAA ovules developed well but there was little or no development of LAA × LL/OO endosperm. The endosperm genome composition of LAA × AA, LAA × AAAA, LAA × LL, LAA × OO are theoretically derived as 5A + 2L, 6A + 2L, 4A + 3L, 4A + 2L + O, respectively. Genomic in situ hybridization showed that the progenies of LAA × AA/AAAA were aneuploid. Based on the experimental results and analyses, our hypothesis is that five same genomes of endosperms are essential for its development in triploid × diploid/tetraploid crosses of Lilium. The hypothesis can explain the success or failure of 3x × 2x/4x crosses in Lilium and is of importance for lily breeders who need to know the likelihood of success when producing new cultivars of this economically important horticultural crop.