Application Of Several Harmless Flower Thinning Agents And Fruit Thinning Agents In Apple

Apple(Malus domestica Borkh.)is one of the four major fruits and plays an important role in China ’s apple industry.With the continuous development of China ’ s economy,light and simplified cultivation and management of fruit trees has become the direction of industry recognition.Because apples have a high natural blooming volume and a rapid fruiting rate,a big number of blossoms will deplete tree nutrients,affecting not only the fruit quality but also the next year’s flowering,resulting in the occurrence of small-output and large-output years.As a result,apple flower and fruit thinning has developed into a critical component of apple flower and fruit management.The majority of orchards in China rely heavily on manual flower and fruit thinning,which is time-consuming and labor-intensive and cannot keep up with the demands of the modern apple industry for cost savings and efficiency gains,whereas chemical flower and fruit thinning techniques can compensate for the shortcomings of traditional manual flower and fruit thinning.The experiment was done in an apple producing location on the Loess Plateau;CFA and TMN-6 were used to determine the influence of various flower thinning timings on fruit set and sensory quality of ’Fuji’,’Ruiyang’,and ’Ruixue’ apples.We evaluated the impact of several flower thinning methods on the fruit set rate and sensory quality of ’Fuji’,’Ruiyang’,and ’Ruixue’.To examine the influence of various thinning agents on the fruit set rate and sensory quality of ’Fuji’,’Ruiyang’,and ’Ruixue’,we used ethephon,NAA,and metamitron,as well as a combination of these three agents,as fruit thinning agents.The effects of several fruit thinning agents on the thinning effect and input cost of ’Fuji’,’Ruiyang’,and ’Ruixue’ were researched in order to identify fruit thinning agents that are suited for various kinds.The following findings were made:1.Three varieties of ’Fuji’,’Ruiyang’ and ’Ruixue’ were treated with chemical thinning.CFA-Ⅱ(10 g/L CFA was sprayed once at 75% of central blooming,40% of whole tree flowering,and 60% of whole tree flowering)had good flower thinning effect in three varieties.The fruiting rates of inflorescences were 61.47%,50.93 %,and 60.87%,respectively.TMN-6-Ⅱ(0.5 mg/L TMN-6 was sprayed once at 75% of central blooming,40% of whole-tree flowering,and 60% of whole-tree flowering)showed good flower thinning effect on ’Ruixue’.Inflorescence fruit setting rate 68.22%.2.When the center fruit diameter was 6 mm and 10 mm,chemical thinning was carried out on ’Fuji’,’Ruiyang’ and ’Ruixue’.On Fuji,C2(20 mg/L NAA + 0.5 g/L metamitron)and S1 treatment(0.4 g/L ethephon)had better fruit thinning effect and were suitable for Fuji fruit thinning.The calyx removal rates were 57.71% and 59.64%,respectively,and the inflorescence fruit setting rates were 68.35% and 64.07%,respectively.The small fruit phenomenon of C3 treatment(0.4 g/L ethephon + 20 mg/L NAA)was serious,and the small fruit rate was 36.18%.In ’Ruiyang’,C2(20 mg/L NAA + 0.5 g/L metamitron),C3(0.4 g/L ethephon + 20mg/L NAA)and S3 treatment(0.5 g/L metamitron)had stable removal effect and were suitable for ’Ruiyang’ fruit thinning.The calyx removal rates were 64.50%,57.35% and49.07%,respectively.The inflorescence fruit setting rates were 66.36%,63.38% and76.23%,respectively.The small fruit phenomenon of S2 treatment(20 mg/L NAA)was relatively serious,and the small fruit rate was 24.13%.There was a risk of excessive elimination in its treatment.In ’Ruixue’,the fruit thinning effect of S3 treatment(0.5 g/L metamitron)is better,suitable for ’ Ruixue ’ fruit thinning agent,followed by C3 treatment(0.4 g/L ethephon +20 mg/L NAA).The calyx removal rates of S3(0.5 g/L metamitron)and C3 treatments(0.4 g/L ethephon + 20 mg/L NAA)were 64.91% and 70.38%,respectively,and the inflorescence fruit setting rates were 69.12% and 60.66%,respectively.S2 treatment(20mg/L NAA)of small fruit phenomenon is more serious,small fruit rate is 31.59%,the risk of excessive treatment.3.Chemical flower thinning and chemical fruit thinning had no significant effect on fruit quality such as soluble solids,titratable acid,density,fruit shape index,color and hardness.but they can greatly save costs and save time and labor;Chemical thinning can save 47% ～ 66% cost than artificial thinning.Chemical fruit thinning can save 56% ～ 81%cost than manual fruit thinning.