Effects Of Plant Growth Regulators And Ring Cutting Treatments On Branching And Flowering Of Pear Trees

Most pear varieties have the characteristics of strong germination rate and weak branching ability,which makes it easy for young trees to form single-stem seedlings,which is not conducive to pear tree shape construction and early fruit yield.At present,the commonly used techniques for promoting branches and flowers in pear pruning are branch pulling,ring cutting,etc.However,these techniques are complicated and laborious.The use of various growth regulators to promote the branching and flowering of pear trees is relatively simple and efficient.It is of great significance for realizing the orientation and positioning of young trees,accelerating the formation of young trees,and early results.In this experiment,‘Dangshan’pear seedlings were used as test materials to study the effects of different plant growth regulators on the branching.In addition,the one-year-old branches of‘Pucheng’pear,vigorous‘Abate Fetele’pear and‘Dangshan’pear were treated with ring cutting,removing apical buds,spraying plant growth regulators and exogenous polyamines,and the effects of each treatment on the branching and flowering of pear trees were analyzed.In order to screen out the optimal combination and concentration of plant growth regulators to promote the branching and flowering of seedlings and saplings,and provide a theoretical basis for the cultivation of pear seedlings and branches in China.The main results are as follows:1.Using‘Dangshan’pear seedlings as materials,the seedlings were sprayed with 6-BA,GA₃,‘6-BA+GA₃’,promalin and KT-30 reagent respectively.The results showed that 6-BA and promalin at different concentrations had obvious effects on the germination and branching,both of which could significantly improve the germination rate,branching ability,medium and long branch rate and average branch length,and promote the basal branches of seedlings.6-BA was best treated with 300 mg/L,and promalin was best treated with 1000mg/L2.Using‘Pucheng’pear as the material,the one-year-old branches were treated with ring cutting,apical bud removal,‘ring cutting+apical bud removal’,300 mg/L 6-BA,100μmol/L MT and‘300 mg/L 6-BA+100μmol/L MT’.The results showed that‘300 mg/L6-BA+100μmol/L MT’treatment had the best branching effect,and‘ring cutting+apical bud removal’treatment had better flowering effect.3.Using vigorous‘Abate Fetel’pear as the material,the one-year-old branches were treated with ring cutting,apical bud removal,‘ring cutting+apical bud removal’,300 mg/L6-BA,100μmol/L MT and‘300 mg/L 6-BA+100μmol/L MT’.The results showed that each treatment could achieve certain branching promotion effect,with‘300 mg/L 6-BA+100μmol/L MT’being the best treatment,followed by 300 mg/L 6-BA alone.However,the flowering rate of both was smaller than that of the control,indicating that 6-BA had a certain inhibitory effect on flower bud differentiation.Overall,the‘300 mg/L 6-BA+100μmol/L MT’treatment was more effective in promoting branching,and the’ring-cutting+terminal bud removal’treatment was more effective in flowering.4.Using‘Dangshan’pear upright branches as material,11 different treatments were conducted on them.The results showed that all treatments could promote thickening growth and branching;the treatment of‘Ring cutting+300 mg/L 6-BA’had the best effect,and 300mg/L 6-BA alone had better effect than ring cutting.5.The results of spraying different concentrations of PP₃₃₃,ETH,Spm,Spd and Put on‘Dangshan’pear showed that PP₃₃₃and ETH could significantly promote the flower bud differentiation of‘Dangshan’pear,and the effect of mixed treatment was better than that of individual treatment.The fruit weight and soluble solids content of‘Dangshan’pear increased to different degrees after treatment,and the stone cell content and flesh hardness were lower than the control,indicating that the spraying of PP₃₃₃and ETH could improve the fruit sweetness and taste to a certain extent and improve its quality,as well as increase the yield of the fruit tree;while the different concentrations of Spm,Spd and Put treatments had different effects on the fruit quality and taste of‘Dangshan’pear,Spd and Put treatments increased the flowering rate of short shoots and medium-length shoots to different degrees,which was especially obvious on medium-length shoots,but their effects on fruit quality were not significant.