| The Malus pumila cv.FuJi is the most important apple cultivar in China.Because of the existence of sporophytic self-incompatibility(SSI),pollination requirements can only be met by configuring other varieties of pollination trees.However,due to improper configuration of pollination trees in current production,poor pollination and fertilization result in serious impact on the improvement of yield and quality.Therefore,reasonable selection of pollination tree has important significance for its yield and quality.In this experiment,eight species of crabapples and Malus pumila cv.FuJi were used as test materials.The biological characteristics of crabapples were investigated to identify and hybridize the pollen vitality.The pollen germination and pollen tube elongation of the stigma were observed by fluorescence microscopy.In the case of entering the ovary,the hybridization affinity was determined and the fruit setting rate after hybridization was counted.From the perspective of affinity,it aims to provide a basis for the selection of special pollination varieties for Malus pumila cv.FuJi.The main findings are as follows:1.By observing and recording the phenophase of flowering,it was found that the eight crabapples were basically ahead of the florescence of the Malus pumila cv.FuJi,or the flowering period met.Artificial pollination to collect pollen in advance,generally in the early flowering period.The study found that the early flowering period of M.halliana,M.‘Red Splendor’ and M.‘Pink spire’ was early;the early flowering stage of the M.‘Radiant’ and theM.‘Strawberry Jelly’were early,and it was different from the flowering period of theMalus pumila cv.FuJi at the initial flowering stage.About 5 days,when collecting,it is necessary to pay attention to whether the pollen is viable and pay attention to the storage of pollen.The M.‘Kelsey’ and the M.micromalus were late in flowering,and the M.‘Sparkler’ was a late flowering variety.If these eight species of crabapples are used as pollinating trees,it can be seen that the flowering period of the eight crabapples is basically the same as the flowering period of the Malus pumila cv.FuJi,and the flowering period is longer than the flowering period of the Malus pumila cv.FuJi and is suitable as a pollination tree.2.Determine the germination rate of eight kinds of ornamental crabapple varieties in different concentrations of medium in order to select the most suitable medium components.The germination rate of pollen was highest in the M.‘Red Splendor’,theM.‘Pink spire’,theM.‘Radiant’ and theM.‘Kelsey’ Japonica under medium of 10% sucrose,0.1% boric acid,1% agar.10% sucrose,0.2% boric acid,1% agar are the best medium for theM.‘Sparkler’ and theM.micromalus.TheM.halliana was 8% and the boric acid concentration was 0.2%.3.The results of pollen germination rates of different crabapple varieties showed that the highest germination rate of the M.‘Sparkler’ was 92.33% under the optimum medium concentration.Followed by the M.‘Pink spire’,the germination rate was 89.53%.The germination rate of the M.‘Red Splendor’ and theM.‘Radiant’was all above 80%.The M.halliana had the lowest germination rate.The germination rate of the M.‘Pink spire’ was faster than that of other varieties.Although the germination rates of the M.‘Red Splendor’ are relatively close to theM.‘Radiant’,in the same period of time,the germination rate of theM.‘Radiant’ is higher than that of the M.‘Red Splendor’.4.Under the fluorescence microscope,the status of the pollen tubes after hybridization in the style was observed: The hybrids of the M.halliana were incompatible with the Malus pumila cv.FuJi.Only a small amount of pollen germinated on the style,and the pollen tube appeared twisted,coiled and irregularly accumulated in the process of extending into the style.The hybrids of the M.‘Kelsey’,the M.‘Pink spire’,the M.micromalus and the Malus pumila cv.FuJi have less pollen germination,and the pollen tubes are twisted and twined,and only a small number of pollen tubes extend into the style and reach the embryo sac.Shows lower affinity.The hybrid ofM.‘Radiant’andthe Malus pumila cv.Fu Ji has strong affinity.The hybrids of M.‘Sparkler’ and the Malus pumila cv.FuJi showed higher affinity.After pollination,pollen could germinate in large quantities and could be rapidly ascended into the style to reach the embryo sac.5.Statistics of fruit set rate after 15 days of hybridization: The hybrid fruit set of M.‘Sparkler’ and the Malus pumila cv.FuJi was 41.6%,which was significantly higher than other varieties.There was no significant difference in the rate of fruiting of the M.‘Red Splendor’,the M.‘Pink spire’,the M.‘Radiant’ and the fruit setting rate was about 30%.The results of cross-fertilization of the M.micromalus,theM.‘Kelsey’,the M.halliana were 16.7%,11.1%,and 8.3% respectively.The three varieties have a low rate of fruit set.Through the comprehensive analysis of flowering period,pollen vigor,and affinity,the following conclusions are drawn: the M.‘Strawberry Jelly’ is pollen-free,and there may be male infertility.Further experiments are needed to prove it.The pollen viability of the M.hallianais low and its incompatibility with the hybrid of the Malus pumila cv.FuJi is low.Both species should not be pollinated trees.The vigor of the M.micromalusand the M.‘Kelsey’,the affinity of the hybrids,and the fruit setting rate were all relatively low and were not suitable for pollination trees.Although pollen vigor is strong,there is incompatibility after hybridization,but the pollen tube can also reach the embryo sac and the fruit set rate is more than 30%.theM.‘Red Splendor’ is suitable for pollination trees.After pollination,pollen sprouted later,but a large number of pollen tubes extended into the style and reached the ovule successfully.The affinity was strong and could be used as a pollination tree.Pollens of M.‘Sparkler’ and the M.‘Radiant’ have high vigor and can germinate rapidly after pollination,and there are a large number of pollen tubes extending into the style,eventually entering the ovule to complete fertilization,and the fruit set rate is also higher than other varieties,from the perspective of affinity can be used as a pollination tree.However,whether or not it can be used as an excellent pollination tree depends on a comprehensive evaluation of the quality of the fruit after pollination. |
