Superior Types Selection And Seedling Quality Grading Of Koelreuteria Paniculata Laxm.in Beijing Area

Koelreuteria paniculata Laxm.has high ornamental value,high application value and strong adaptability,and it is an excellent native tree species with the great promotion prospects for landscaping in china.In order to select high ornamental value superior types Koelreuteria paniculata Laxm.,the study Investigates and preliminary select some Koelreuteria paniculata Laxm.with good growth condition,and investigate of its phenological characteristics and morphological indexes.to evaluates the ornamental value of Koelreuteria paniculata Laxm.in Beijing Area.In addition,the study sets the seedling quality grading standard of Koelreuteria paniculata Laxm.through the investigation of annual and biennial Koelreuteria paniculata Laxm.seedlings' growth condition in Beijing city.And this is conducive to the selection of high quality stock for further grafting of high ornamental value Koelreuteria paniculata Laxm..The main results are as follows:1.Through Investigating Koelreuteria paniculata Laxm.in Jiufeng area and Dadongliu nursery plantation.Preliminary systematically,preliminary selecting 61 representative Koelreuteria paniculata Laxm.with good growth condition.Survey results show that:first-flowering dates of Koelreuteria paniculata Laxm.are widely distributed from late May to early August in Beijing city,and are distributed mainly in June;flowering duration is generally 15?20 days,a few can last about 30 days;first-fruiting dates of Koelreuteria paniculata Laxm.are distributed from mid June to late August,and are distributed mainly in late June to early July;Koelreuteria paniculata Laxm.fruit can develop to mature gradually after 30??40 days.2.Using the AHP to establish the evaluation model of Koelreuteria paniculata Laxm.ornamental value including the target layer(A),constrained layer(C),standard layer(P),the lowest layer(D)4 levels and 15 evaluation indexes,and the model is used to evaluate 61 Koelreuteria paniculata Laxm.ornamental value,for further selecting of superior types Koelreuteria paniculata Laxm..The evaluation results are divided into 4 levels:Grade ? has 5 trees;Grade ? has 14 trees;Grade ? has 27 trees;Grade? has 15 trees.The Grade ? belongs to superior types Koelreuteriapaniculata Laxm.and have great development potential because of their high ornamental value,and they can be used as superior types to graft propagation in landscaping.3.The survey finds 7 special types trees of Koelreuteria paniculata Laxm..Because of the unique ornamental value,they can be promoted as the good types.There are 5 trees belong to "late flowering type",Koelreuteria paniculata Laxm.,as compared with the normal,their first-flowering dates are much later until mid August,which belongs to the type of autumn flowering;another 2 trees are "red fruit type",their ripe fruit is beautiful and has very high ornamental value with the bright orange red color.4.Using standard deviation method and cluster analysis on seedling quality grading of annual and biennial Koelreuteria paniculata Laxm.seedlings to set the quality grading standard of Koelreuteria paniculata Laxm.in Beijing city,which based on seedling height and ground diameter.The standards are as follows:Beijing annual Koelreuteria paniculata Laxm.seedlings Grade I,D?22mm,H? 121cm;Grade ?,22>D?16mm,121>H? 85cm;Grade ?,D<16 mm,H<85cm.Biennial Koelreuteria paniculata Laxm.seedlings Grade I,D? 25mm,H? 183cm;Grade ?,25>D? 19mm,183>H? 144cm;Grade ?,D<19mm,H<144cm.According to the grading standard,Grade ? seedlings can be used as a rootstock for grafting propagation.