| Tulips are perennial herbs in the genus Tulipa L.of Liliaceae.There are many cultivars of tulips,but few of them have independent intellectual property rights in China.Therefore,it is necessary to make full use of the unique wild tulip species in China.The excellent traits of wild tulip species in China were transferred to new cultivars by means of cross breeding and other technologies,and new tulip varieties with independent intellectual property rights and suitable for local cultivation were selected.In this study,4 wild tulip species as male parent,3tulip cultivars with special floral patterns and 6 cultivars with different ploidy were used as mother samples.Pollen storage life and viability,pollen morphology,cylindrical grant,interspecific hybridization,pollen tube fluorescence,seed paraffin section,embryo culture and chromosome identification of hybrid progeny were measured.The aim is to explore the compatibility between tulip cultivars and wild hybrids,and to provide a theoretical basis for the future genetic variation of tulip interspecific hybridization and wild species as well as the development and utilization of these wild resources.The results are as follows:1.The pollen morphology of the parents were divided into 4 groups by cluster analysis.Pollen shapes of most varieties are nearly long globular or long globular,with warts on the surface and few perforations or small and sparse perforations,including T.altaica,‘Black Parrot’,‘Purple Dream’,‘Orleans’,‘Golden Parade’,‘Banja Luka’,‘Synaeda Amor’and‘Carnaval de Rio’;‘Crystal Beauty’and‘Judith Leyster’belong to the same group,and their morphological characteristics are nearly long spherical with little difference in P/E values.;T.thianschanica and T.sinkiangensis are a group.The main characteristics of these 2 wild species are that the P/E ratio is basically the same and the ratio is large,the shape is long globular,the decoration of T.sinkiangensis is special,it is shallow wrinkle ripple.The main characteristic of this species is that the P/E ratio is very large and the shape is super long globular.T.altaica are the closest wild species to the cultivars in pollen morphology.2.Pollen viability was different under different determination methods.The viability of the 4 male parent pollens showed TTC staining>liquid medium>solid medium.T.altaica showed high vigor in the 3 kinds of determination results,which were 85.7%,70.8%and55.2%,respectively.Next is T.sinkiangensis,the results were 76.1%,56.4%and 45.8%.The pollen vigor of T.thianschanica was similar to that of T.patens,65.3%,50.0%,16.8%and67.6%,53.6%,13.2%,respectively.Different temperatures also have a great influence on the storage life of pollen.The results showed that after 60d of storage under-20°C,the pollen vigor of T.altaica（18.74%）,T.sinkiangensis（17.7%）,T.thianschanica（21.6%）and T.patens（22.2%）remained at about 20%respectively.However,under 20°C conditions,the viability of4 species of male pollen decreased to less than 3%,and the viability of T.thianschanica decreased to 0.For the female parent,the stigma of tulip cultivars was the highest on flowering day T3（12:00,noon）,but with the advance or extension of flowering time,it showed a downward trend.3.By fluorescence observation of pollen tube elongation of the interspecific hybridization of Black Parrot（2x）×T.altaica（2x）,it was found that a few pollen grains had germinated and the pollen tubes had a certain length elongation 4 hours after pollination.At 6hours after pollination,the pollen on the surface of stigma began to germinate in large quantities and grew by bending.12 hours after pollination,pollen tubes grow in bundles,tightly wound,leading to the base of stigma;24 hours after pollination,some pollen tubes enter the ovary and complete the fertilization process.However,for the incompatible hybrid Black Parrot（2x）×T.sinkiangensis（2x）,the pollen grains did not begin to germinate after pollination 4 hours,and the number of full pollen grains was very small,and there were many dried pollen grains.At 8 hours after pollination,a few pollen grains began to germinate and pollen tubes began to elongate.From 8 to 24 hours after pollination,the pollen tube slowly extended to the stigma,slightly twining,and reached the stigma at 24 hours after pollination.48 hours after pollination,the pollen tube growth abnormal,began to intertwined,part of the pollen tube began to expand and become thick,stigma there are many callose,so that the pollen tube stopped growing,hybridization obstacle is serious.Paraffin sections,like most monocotyledonous plants,tulip hybrid embryo develops from zygote embryo to pear-shaped embryo and shield embryo,and mature embryo at last.4.The embryo age of tulip hybrid embryo is different to have a great effect on seed embryo germination and seedling formation of tulip.All hybrid embryos of different hybrid combinations showed that when the embryo age was 20 d,the germination rate and seedling formation rate of hybrid embryo culture were very low,the germination rate was 6.7-13.3%and the seedling formation rate was 0-6.7%.The embryo with 40 d and 50 d is the closest to maturation,the volume of seed embryo is large,it is easy to separate from endosperm,the germination rate and seedling formation rate are also the highest,the germination rate is43.3%-86.7%and the seedling formation rate is 30%-76.7%.The germination rate of young hybrid embryos with different hybrid combinations was also different on the same medium.Of the 3 hybrid combinations,MS+NAA 0.01 mg/L+BA 0.1 mg/L was the most suitable medium.5.Among the 4 wild tulip species,tulip cultivar was more likely to cross with T.thianschanica and T.altaica successfully,and a total of 9 cross combinations obtained seeds,with the number of seeds being 41-316.The success rate of hybridization with T.sinkiangensis and T.paten is low,capsule bulges 11.43%-51.52%,but no seeds were obtained.The hybrid seed setting of tulip varieties with different ploidy was different from that of wild species,the seed setting rate of triploid,tetraploid and wild species is low.In 16 hybrid combinations,only 3 combinations were strong.The rest of the combinations,though varying degrees of enlargement,without getting the seeds.Hybridization between wild species and diploid,The fruiting rate is relatively high,410 seeds were obtained.The number of chromosomes was counted by interspecific hybridization progenies.Banja Luka（3x）×T.altaica（2x）hybrid progenies had euploidy and aneuploidy,the number of chromosomes was36,36 and 31 respectively.Banja Luka（3x）showed the same in the hybrid progenies of T.thianschanica,with 36,35 and 29 chromosomes,respectively. |
