Study On Screening Of Pollination Varieties And Flower Bud Morphological Differentiation Of ’Bramley’s Seedling’ Apple

The pollen viabilities of ‘Mollie’s’,‘Redchief’,‘Dahongrong’,‘Red Fuji’,‘Gala’ and ‘Grieve’(the control),and the effects of pollination on fruit setting,fruit growth and fruit quality of ‘Bramley’s Seedling’ apple and its flower bud morphological differentiation were studied,aiming at selecting the appropriate pollination trees for ‘Bramley’s Seedling’ apple and providing ‘Bramley’s Seedling’ apple cultivated in Tianjin and other areas with similar climate and soil conditions as well as formulating corresponding cultivation management measures with theoretical support.The results showed that ‘Mollie’s’ had the highest pollen viability in all six tested cultivars,followed by ‘Redchief’,with the lowest pollen viability for ‘Grieve’ based on pollen germination tests in vitro and on stigma.The pollen viabilities increased at the beginning and then declined with prolong of storage time,reaching its maximum value in two to four months.Putting the pollens into vacuum dryer in refrigerator was a favorable storage conditions to the storage of tested pollen.The mediums with different ingredient combination were necessary to match with pollen germination or tube growth of the distinctive apple cultivars.In general,viabilities of the tested pollen can be ranked as ‘Mollie’s’ > ‘Dahongrong’ > ‘Redchief’ > ‘Red Fuji’ > ‘Gala’ > ‘Grieve’.‘Bramley’s Seedling’ pollinated with ‘Mollie’s’ pollen appeared the significant highest fruit setting rate and the highest extractable juice content in all the pollination combinations.The fruits setting rates of the plants pollinated with all of tested cultivars,except for ‘Gala’,were higher than that pollinated with the control ‘Grieve’.Of the soluble sugars and titratable acids,the apple pollinated with ‘Dahongrong’s pollen held the highest content,which was very significant higher than that pollinated with the control.The highest single fruit weight appeared in the combination with ‘Gala’ pollen.When ‘Red Fuji’ was used as pollination cultivar,the fruits held the significant higher content of soluble solid substance than those pollinated with other cultivars and the highest firmness in all.According to the pollination experiment,the average value of membership function analyzed by the fruit characters of ‘Bramley’s’ can be ranked as ‘Mollie’s’ > ‘Dahongrong’ > ‘Redchief’ > ‘Gala’ > ‘Red Fuji’ > ‘Natural pollination’ > ‘Grieve’.‘Bramley’s Seedling’ initiated the stage of flower bud morphological differentiation around June 14 th,with a few flower bud primordium differentiation at the same time,and started sepals formation period around June 21 st,petal and stamen primordium differentiation around July 4th,and pistil formation period around July 12 th.There were overlaps between each period of morphological differentiation.There was no obvious variation in the ratio of N,P,K content in ‘Bramley’s’ leaves before flower bud morphological differentiation started while appeared ones after that.Conclusions can be drown from the pollen viabilities of tested cultivars and the pollination effects that ‘Mollie’s’,‘Dahongrong’ and ‘Redchief’ can be used as appropriate pollination cultivars when ‘Bramley’s Seedling’ is planted in Tianjin and the areas with similar site conditions.The period of flower bud morphological differentiation of ‘Bramley’s Seedling’ started at June 14 th,finished around September 21 st and lasted about 100 days.