Studies On Labor-saving Fruit Thinning And Promoting Fruit Enlargement Practices In Ponkan

Known as"the king of the Asian Mandarin",ponkan?Citrus reticulate Blanco?is famous for its large fruit,easy peeling and fine taste.In particular,ponkan is generally favored by consumers for its biggest fruit?>70 mm?.The bigger the fruit,the better the quality,and the higher the price.Therefore,the production of ponkan can greatly improve the income of fruit farmers.Using blossom and fruit thinning agent is an important means to improve fruit size and quality.However,the lack of labor force and the rise of labor costs become the important factor of limiting the development of citrus industry.So it is necessary to study the technology of laborsaving culture to ensure the sustainable development of citrus industry in the future.Therefore,it is of great significance to study the production technology of ponkan,which is of great importance to reduce the cost of production and improve the economic benefits.Previously,the chemical reagent hydrophobic fruit was often studied on deciduous fruit trees.However,there is little research on citrus,especially ponkan,which is not applied to actual production.In this research,we use Ponkan as experimental material to explore the effect of the percentage of setting fruit,fruit size,yield and quality of Ponkan fruit by using blossom and fruit thinning agent,the growth regulator and delayed fruit expanding fertilization.The results are as follows:1.Effect of chemical reagent on ponkan fruit thinning and fruit quality?1?Lime sulphur:It has obvious effect of blossom and fruit thinning when spray sulfur mixture?1³°Bé?at flourishing flowering stage or one week later for 2³°Béand the fruit setting rate is only about half of the control,the treatment in flowering stage is better than a week after flowering;Among these,increase the ratio of biggest fruits up to 37%when spray 2°BéLime sulphur and the content of unit volume and soluble solids increased significantly.?2?Ethephon:Similarly,three different periods?full bloom,a week after full bloom or two weeks after full bloom?had a significant thinning effect with a spray of50?100 or 150 mg/L of ethephon and the fruit setting rate is less than 5.5%.During the blooming period,the amount of ethylene gas injected 100 mg/L could increase the ratio of biggest fruits up to 52%in the case of increased yield,the average diameter of the fruit reached 69.8mm and the titratable acid content was significantly reduced and the solid acid ratio was improved.?3?Naphthylacetic acid:All of them can achieve remarkable effect of blossom and fruit thinning when spraying three concentrations?200,400 and 600 mg/L?of naphthylacetic acid whether at a week after full bloom or two weeks after full bloom and the fruit setting rate was below 6.5%.Under the premise of guaranteeing the yield,the fruit size and the ratio of the largest fruit were increased by 14%when spray 200mg/L naphthylacetic acid at a week after full bloom or two weeks after full bloom.It can also increase soluble solid content and decrease titratable acid content and then increase the ratio of soluble solid content to titration acid.?4?3,5,6-TPA:There was no obvious thinning effect of spraying 10 mg/L of3,5,6-TPA in the middle stage of the second physiological fruit-falling period while there was a remarkable thinning effect of spraying 20?30 and 40 mg/L and the fruit setting rate is only about 1%.Among them,under the premise of guaranteeing the yield or even increased,the fruit size was significantly increased with the treatment of20³0 mg/L of 3,5,6-TPA.The ratio of large fruit was more than 80%and the average diameter of the fruit was above 75 mm.All treatments significantly increased the content of soluble solids and decrease titratable acid content and then improve fruit quality.2.The effect of plant growth regulator on the production of high quality biggest fruit in Ponkan.?1?2,4-DP:Spraying 2,4-DP of 50 mg/L can significantly increase fruit size and the ratio of biggest fruit were increased by 14%in the middle of the second physiological fruit-falling period.The other two treatments significantly increased the yield,but had no significant effect on fruit size.All treatments significantly improved the soluble solid content and titratable acid content and decrease solid acid rate.?2?2,4-D+5%KNO₃:Although the proportion of biggest fruit increased,the proportion of bigger fruit decreased and the distribution frequency of small fruit did not change when spray 2,4-D+5%KNO₃ of 20 mg/L in the middle of the second physiological fruit-falling period.Although the ratio of biggest fruit did not change,the distribution frequency of small fruit was significantly reduced,the ratio of bigger fruit was increased and the yield was increased obviously and the fruit quality was not affected.?3?Compared to fertilization before the end of the second physiological fall?30June?,the fruit setting rate of fruit expanding fertilization dropped to 4.69%and 6.95%respectively at the end of physiological fruit drop?July 10?and at the end of 10 days?July 20?,both of which significantly reduced the proportion of small fruit.The ratio of large fruit and the average cross diameter of fruit increased by about 11 percentage points and 4 mm respectively when fertilization was applied about 10 days after the end of the second fruit drop?July 20?and it has no effect on yield and fruit quality.In practice,chemical defoliation and fruit thinning can be combined with the technology of promoting fruit enlargement.On the basis of the routine management,spraying 2°Bélime sulfur agent for chemical thin flower thinning and reducing nutrient competition at full-bloom stage;The medium term of physiological fruit drop was supplemented by 50 mg/L,2,4-DP to promote fruit swelling;After the end of the physiological fruit,the fruit was fertilized for 10 days or so?20 July?,which provided sufficient nutrients for the fruit swelling.Through a series of systematic cultivation measures,the goal of reducing production cost,improving fruit size and quality,and improving economic benefit is finally achieved.