| Camellia oleifera Abel.is a key woody oil crop for development in China.The vigorous development of the camellia oleifera industry is one of the strategies for the development of China’s oil crop industry,helping to meet the growing domestic demand for healthy and high-quality vegetable oil,achieving the strategic goal of self-sufficiency in domestic food and oil,helping to promote the development of rural revitalisation industries,and realising the unity of ecological and economic benefits.All along,the problem of low yield of camellia oleifera in China has existed for a long time,which seriously hinders the healthy development of the camellia oleifera industry.In order to solve the problem of low yield of camellia oleifera,previous research has been conducted on low yield forest transformation methods,but no standardized technical operation specification has been formed,which is difficult to be applied in the large-scale camellia oleifera low yield forest transformation work.Therefore,to address the problem of low-yielding camellia oleifera forest transformation,this study conducted camellia oleifera grafting for crown replacement trials and camellia oleifera pruning trials.1.Camellia oleifera grafting for crown replacement testThe low-yielding 7-year-old camellia oleifera plants with no fruit or little fruit were selected as rootstocks,and the spring tips of Cen-Ruan-3 7-year-old high-yielding camellia oleifera plants were used as scions.Six grafting methods,including single-bud ventral grafting,concave ventral grafting,double-forming layer butt grafting,pith-forming layer butt grafting,shield-shaped bud grafting and inserting bark grafting,were used for grafting and crown replacement experiments.the results of the trials are as follows:(1)The effect of different grafting methods on the survival rate:Through the analysis of the survival rate of six grafting methods,it was found that different grafting methods had a significant effect on the survival rate,and the survival rate from high to low was inserting bark grafting>shield-shaped bud grafting>pith-forming layer butt grafting>single bud ventral grafting>double-forming layer butt grafting>concave ventral grafting.The survival rate of concave ventral grafting was the lowest at 48.71%,while the survival rate of skin grafting was the highest at 80.39%,giving the best results.(2)Effect of different grafting methods on growth:The growth of the scions was measured in terms of turgor rate,new shoot length and number of branches one year after grafting,and the analysis revealed that different grafting methods had a significant effect on growth.The best results in terms of turgor rate were obtained with a 90.08%turgor rate.In descending order,the rate of turgid grafting was:inserting bark grafting>concave ventral grafting>pith-forming layer butt grafting>double-forming layer butt grafting>single bud ventral grafting>peltate bud grafting.Of the six grafting methods,the highest new shoot growth of 50.82 cm was achieved by skin grafting,and the order of new shoot growth was,in descending order,skin grafting,concave ventral grafting,double forming layer buttressing,single shoot ventral grafting,peltate budding and medullary forming layer buttressing.The branching of new shoots was,in descending order,inserting bark grafting>concave ventral grafting>double-forming layer buttressing>single bud ventral grafting>pith-forming layer buttressing>peltate budding,with skin grafting having the best branching,averaging 3.55 branches.In a comprehensive evaluation of the three aspects,namely the rate of tapping,the amount of new growth and the amount of branching,the six grafting methods had the best growth.(3)Survey on the growth of camellia oleifera with inserting bark grafting:after two years of grafting,the growth of camellia oleifera with inserting bark grafting was investigated and found that the fruiting rate of the grafted branches reached 65%and the grafted branches with more flower buds accounted for 70%.2.Camellia oleifera pruning testsFour treatments and one control were set up to prune the Xiang-Lin-210 low yielding camellia oleifera plants by retaining 1/5,2/5,3/5,4/5 and no pruning of the crown.the results of the trials are as follows:(1)Effect of different pruning levels on the growth of camellia oleifera:By analyzing the crown diameter,crown height and crown volume of camellia oleifera after pruning,it was found that different pruning levels had significant effects on the growth of camellia oleifera.The crown diameter of camellia oleifera was in descending order of treatment 3>control>treatment 2>treatment 4>treatment 1,with the longest crown diameter of treatment 3 being 2.39 m.The crown height of camellia oleifera was in descending order of control>treatment 4>treatment 3>treatment 2>treatment 1,with the highest crown height of control group being 2.15 m.The crown volume of camellia oleifera with different pruning levels was in descending order of treatment 3>treatment 2>control>treatment 4>treatment 1,with treatment 3>treatment 2>treatment 4>treatment 1.4>Treatment 1,with the largest canopy volume of 4.10 m~3in Treatment 3.(2)Effect of different pruning levels on camellia oleifera yield:The yield of camellia oleifera was significantly increased after pruning,with all treatments significantly larger than the control,with the largest yield of 1.54 kg in treatment 3,an increase of 90.12%compared to the control.The yield per plant in each group was in descending order:treatment 3>treatment 2>treatment 4>treatment 1>control.The yield per unit volume was in descending order of treatment 1>treatment 4>treatment 2>treatment 3>control,with treatment 1 having the largest yield per unit volume,2.89 times that of the control.(3)Correlation analysis of camellia oleifera yield with crown diameter,crown height and crown volume:The correlation analysis between camellia oleifera yield and crown diameter,crown height and crown volume revealed that crown volume was significantly and positively correlated with yield,with the correlation coefficient being crown volume>crown diameter>crown height in descending order.In general,the six grafting methods in the grafting test had significant effects on survival rate and growth volume,among which the survival rate and growth volume of the plug-skin grafting were the best and most suitable for use in the transformation of low-yielding camellia oleifera forests;in the pruning test,the pruning measure of 3/5crown retention was the most effective and most suitable for application in production,based on the overall growth and yield index of camellia oleifera. |
PDF Full Text Request