Effects of Different Seasons on Cutting Propagation of Five Citrus Rootstocks

[Objectives]To explore the cutting propagation mode of citrus rootstock,improve the survival rooting rate of citrus rootstock,and provide theoretical guidance and technical reference for the rooting research of difficult-to-root plants such as citrus.[Methods]Five citrus rootstocks Citrus tangerina Tanaka‘Hongju’,Citrus haniana Hort‘Suanju’,Citrus limonia Osbeck‘Hongningmeng’,Citrus sinensis×Poncirus trifoliata‘Zhicheng’and Poncirus trifoliate(L)Raf.‘Zhike’were used as experimental materials to select the suitable cutting substrate for citrus rootstocks by measuring the physical properties of the substrate.Cutting was carried out in spring,summer,autumn and winter respectively.After cutting,the morphological changes of cuttings were observed regularly,and the callus rate,germination rate and rooting rate of cuttings were recorded.[Results]The best substrate for citrus rootstock cutting was peat soil,vermiculite and fine river sand(2:1:1).The callus of citrus rootstock in different cutting seasons began to appear in 10-22 d,and the callus rate reached 55%-100%.In terms of budding,the budding time was the earliest in summer and autumn,and slightly later in spring and winter;the germination rate of C.limonia Osbeck‘Hongningmeng’was the highest,and the germination rate of C.sinensis×P.trifoliata‘Zhicheng’and P.trifoliate(L)Raf.‘Zhike’was lower;in terms of rooting,C.limonia Osbeck‘Hongningmeng’had the earliest rooting time and the highest rooting rate and could reach 100%in all seasons;the rooting rate of C.tangerina Tanaka‘Hongju’was 50%-80%;the rooting rate of C.haniana Hort‘Suanju’was 60%-80%;C.sinensis×P.trifoliata‘Zhicheng’and P.trifoliate(L)Raf.‘Zhike’showed the earliest rooting time and the highest rooting rate in summer,and the latest rooting time and the lowest rooting rate in winter,which were only 14.5%.Therefore,different citrus rootstock varieties should choose the appropriate cutting time according to their own characteristics.[Conclusions]The results of this study can provide a scientific basis for a large number of cutting propagation of different citrus rootstocks,and have practical guiding significance for large-scale planting.

Study on Hardwood Cutting Propagation Technology of Fraxinus

[Objective] Hard-branch cutting propagation technology of Fraxinus was studied under different environmental conditions. [Method] An orthogonal test was designed based on 1-year-old clones of F. pennsylvanica Marsh Lula 5. Under dif- ferent growth hormones, hormone concentrations and processing time, F. velutina Lula 2 and F. pennsy/vanica Marsh Yuanla 2 were treated by vacuum pump for 10 min, [Result] The decreasing order of cutting survival rates of Lula 5 under different etnvironments was small plastic flowerpot （94.4%）, nutrition cup （92.8%）, sand tray （56.1%）, and cuffings treated with 100 mg/L ABT, for 2 h, 200 mg/L ABT, for 4 h and 100 mg/L IBA for 6 h under large nutrition cup environment grew the best, showing a survival rate of 100%. Lula 2 and Yuanla 2 were subjected to vacuum pump treatment, the survival rate of cuttings under the sand tray environment was averagely 29%; and under the large plastic flowerpot environment, the survival rate of cuttings was averagaly 64.4%, and cuttings of Lula 2 treated with vacuum pump for 10 min in 200 mg/L ABTI showed a survival rate up to 95%, which was the highest among all treatments. It could be seen that whether cuttings were treated with vacuum pump, the survival rate of cuttings in sand tray was lower than those under other environments, while there was no big difference in survival rate of cut- tings between the nutrition cup and plastic flowerpot environments. [Conclusion] This study is of great significance to improvement of cutting propagation coefficient.

Study on Cutting Propagation of Toona ciliata Clones

Cutting propagation rhizogenesis of Toona ciliata clone cutting orchard were studied, and the results were as fol ows： Rooting type included both cal us rooting and cortex rooting. About 17 in 22 of clones were dominated by cortex rooting, accounting for the 77% of clones. There were 5 clones which occurred with both cal us rooting and cortex rooting during rooting process. The rooting efficiency index （REI） showed a positive correlation with the rooting rate. Under natural tem-perature condition, keeping moisture and shading, we found that the highest survival rate occurred in early June, September, and October.

STUDY ON THE CUTTING PROPAGATION TECHNIQUE OF PICEA KORAIENSIS

The cutting propagation technique of Picea koraiensis was carried under automatic spraytng of total sunlight by adopting the same year epicormic branches from different trees with different age treated by different hormones in different concentration and time and the orthogonal and randomized block was designed. The results were as follows : (1)The rooting rate of the cutting reached at least 87 percent, when the cuttings were from the seed tree with the age below 25 years old and the cuts of the cuttings base were in vertical angle and on the fine sand medium. (2) The sequence of effective factors affecting the rooting rate were the style of cut, the age of seed tree and the trpe of mediun. (3) There are significant differences of rooting rate among different clones.

Study on the Cutting Propagation Technique of Rubus spp. Raspberry

[Objective] The research aimed to study the effects of different matrices and hormones on the rooting rate of Rubus spp. Raspberry. [Method] Different ma- trices and different hormones with different concentrations were adopted to design completely randomized block test, thus to conduct cutting experiment of Rubus spp. Raspberry, in order to discuss the effects of different matrices and hormones on the rooting rate of Rubus spp. Raspberry. [Result] The rooting rate was significantly af- fected by different hormones and matrices, whereas the effect of hormone concen- tration was not significant. The suitable combination was 200 mg/kg ABT ＋ river sand. The effect of growth hormone on hard wood cutting of Rubus spp. Raspberry in river sand was not significant. [Conclusion] This test can provide a reference for the industrialized seedling production of Rubus spp. Raspberry.

Study on the Efficient Cutting Propagation Technology for <i>Ilex</i>“China Girl”

In order to realize the efficient industrial production of Ilex “China Girl”, an orthogonal experiment with 4 factors and 3 levels was designed. Firstly, the optimal orthogonal cutting scheme was selected from 9 treatments. Then through the systematic analysis of the effects of cutting position, substrate, exogenous hormones type and concentration on rooting indexes, such as rooting rate, root number, root length and root effect index, the theoretical optimal scheme was predicted and verified. The results showed that the theoretical optimal scheme (3000 mg/L IBA treatment for 15 s, cutting in mixed matrix with peat soil, perlite and vermiculite ratio of 2:1:1) was the optimal cutting rooting scheme of Ilex “China Girl”. After the treatment of this scheme, the rooting rate of Ilex “China Girl” reached 100%, the average root number was 51.67 per plant, and the average root length was 6.13 cm. The rooting time was greatly shortened, the rooting rate and rooting effect were greatly improved. In this study, the efficient cutting propagation technology system of Ilex “China Girl” was established, which laid a foundation for the popularization and application of Ilex “China Girl”, and also provided reference for further improving the cutting propagation efficiency of other evergreen holly. This study laid a foundation for the application of Ilex “China Girl”, and also provided a reference for further improving the cutting propagation efficiency of other evergreen holly.