Study on mineral nutrition optimum parameters of sand pear cultivars by top grafting contrast experiment.

According to the principle of stable difference in mineral nutrition optimum parameters of leaves among fruit tree cultivars,the experiment was carried out to study the nutrition difference of five pear cultivars(Pyrus pyriflia) which grafted on same rootstock.The optimum parameters for the cultivar Cuiguan were used as control.According to the sequence of five cultivars nutrition value,the results of significance test and the upper limit to confidence interval 1.28×Std+d(-) of t test,the mineral nutrition optimum parameters of Huanghua,Qingxiang,Yuguan and Mixue were statistically inferred on the basis of Cuiguan mineral nutrition optimum parameters which had been known.The necessary conditions and limitations of top-grafted contrast experiment as well as the selection of minimum reliable sample size n were discussed.The aim of this paper was to provide a new effective method for research on fruit mineral nutrition optimum parameters by top grafted contrast ex-periment.