Study On Compatibility Of Interspecific Hybrids Crossed With LA And Asiatic Lilies

Lily is a perennial bulbous flower,belonging to the genus Lilium of the family Liliaceae.Crossing hybridization is the main method for breeding new cultivars of horticultural plants,but distant hybridization has become the main method for breeding new cultivars of lily,which is an important feature in lily breeding.In this experiment,the interspecific hybrid progeny produced by distant hybridization was used for interspecific hybridization with 10 cross combinations of LA and Asiatic lilies.Among the hybrids,DB3(2n=2x=24),DC9(2n=2x=24),12-6(2n=3x=36),DD17(2n=2x=24),LA lilies Red Sensation(2n=4x=48),Batistero(2n=3x=36),and Asian lilies Tresor(2n=4x=48),Benfica(2n=4x=48),Aladdin's Dazzle(2n=2x=24)were selected for parents.Pollen viability,pollen amount and stigma receptivity of hybrid parents were determined.The obstacles of pre-fertilization and postfertilization were studied by the observation of pollen tube fluorescence and paraffin section technology of embryo.The hybrid seedlings were obtained by embryo culture technology,the ploidy of hybrid parents and seedlings was identified in order to explore the hybrid compatibility and provide help for breeding excellent and innovative germplasm.The results were as follows:The viability of pollen was measured by the method of germination in vitro.The pollen viability of the hybrids,LA and Asiatic lilies were different.The pollen viability of DD17 was the highest(68.71%)and Batistero was the lowest(5.73%).The results showed that the anther shape,size and pollen amount of different cultivars were different.Among the all materials,the pollen of interspecific hybrid DC9 was the most,553800 per flower;‘DB3' and ‘DD17'were the lowest,211200 per flower.The method of benzidine was used to detect the receptivity of stigma.On the day of flowering(0d),the highest receptivity was observed.The results showed that the cross compatibility index of cross was higher than that of backcross,and cutting stigma could improve the cross compatibility to some extent.The interspecific hybrids as female parent,DC9×Red Sensation had the best compatibility,the conventional pollination compatibility index was 1.15,the cutting stigma increased compatibility,and the compatibility index was 1.75.The results showed that the index of cross compatibility was higher than its reciprocal cross.The interspecific hybrids as female parent,DD17×Aladdin's Dazzle showed a conventional pollination compatibility index of0.88 and cutting stigma pollination compatibility index of 1.69;the compatibility index of conventional pollination was 5.71 and that of cutting stigma was 8.31.The pollen of 9 parents could germinate on the stigma of hybrid.The cross betweeninterspecific hybrids and LA lilies were incompatible except for DC9×Red Sensation,Callose phenomenon appeared in the style of 48-96 h pollination,which hindered the growth and belonged to the pre-fertilization obstacle.The hybrids between lilies and Asiatic lilies were not compatible except DC9×Tresor,Benfica×DB3 and Aladdin's Dazzle×DD17,after pollination,abnormal phenomena occur at different positions of the style at different times,and failure to complete fertilization is a pre-fertilization obstacleThe embryology of DC9×Red Sensation,DC9×Tresor and Aladdin's Dazzle×DD17embryos was observed by paraffin section.The results showed that four cell proembryo was formed by mitosis of zygote twice,pear shaped embryo was formed by four cell proembryo,and shield shaped embryo was formed by pear shaped embryo.The development and maturity time of hybrid embryo of different hybrid combinations were different.The embryo of DC9×Red Sensation pollinated for 38 d was mature,the DC9×Tresor took the least time pollinated for 35 d was fully developed.In the experiment of embryo culture,the germination rate and seedling rate of Aladdin's Dazzle×DD17 embryo were the highest,73.97% and 58.90% respectively,the germination rate of Tresor×DC9 embryo was the lowest,40.00% and 6.67% respectively,the proliferation coefficient of in vitro plantlets from DC9×Tresor was the highest,9.94,and the growth of the plantlets was good.The highest rooting rate of Aladdin's Dazzle×DD17 was 88.79%,and the plant growth was good.The highest survival rate of in vitro plantlets from DC9×Tresor was94.31%.The ploidy of seedlings of some hybrids was identified.The progenies DH,DC and BD obtained from DC9(2n=2x=24)× Red Sensation(2n=4x=48),DC9(2n=2x=24)× Tresor(2n=4x=48)and Benfica(2n=4x=48)× DB3(2n=2x=24)respectively were triploid(2n=3x=36).The progeny hybrid AD obtained from Aladdin's Dazzle(2n=2x=24)× DD17(2n=2x=24)was diploid(2n=2x=24).