Study On Grafting Of Camellia Hainanica Seedlings And Container Seedling

Camellia hainanica germplasm resources have the characteristics of fast growth and large fruits.The growth habit and flower and fruit traits of C.hainanica are significantly different from those of Camellia oleifera.In recent years,Hainan provincial government strongly support the industry of C.haina nica and farmers are highly motivated to plant C.hainanica,resulting in a greater demand for seedlings.However,the climate and ecological conditions in Hainan are very different from those in mainland.Therefore,the production technology of C.oleifera seedlings cannot be directly copied and applied.It is urgent to develop a set of seedling technology system suitable for C.hainanica.In this paper,three C.hainanica cultivars-'Haiyou 1','Haiyou 2' and 'Haiyou 3',selected by Central South University of Forestry and Technology,were used as materials.The systematic researches were performed on grafting period,shading intensity,rootstock screening,container screening,light substrate formulation seedling cultivation and large-scale container seedling cultivation for C.hainanica seedling raising technology.The main results are as follows:1.The effects of different grafting periods and shading intensity on the survival rate and growth of C.hainanica seedlings.In early to mid January and mid-to-late March,'Haiyou 1','haiyou 2' and 'haiyou 3' were tested for grafting,and then the grafted seedlings were transplanted into seedling beds with 50%,70%and 90%shading.The results showed that under shading of 50%,the survival rates of grafted seedlings of three C.hainanica cultivars were low in January and March,with the highest survival rate of 70.53%.When the shading intensity was 70%,the survival rate of grafted seedlings in January is above 94.10%,wheras in March it is less than 85.50%.When the shading degree reached 90%,the survival rate of grafted seedlings in January and March were more than 93.74%.However,with the increase of shading,the seedling height,ground diameter,biomass,and soluble sugar and soluble protein content of grafted seedlings in January and March decreased significantly,whereas the chlorophyll content increased.In the practical production,the shading intensity of grafted seedlings of C.hainanica should reach 90%during seedling raising process.After that,the shading intensity can be gradually reduced to promote the growth of seedlings.2.The effect of different rootstocks on survival rate and growth of C.hainanica seedlings.'Cenruan 1','Cenruan 2',Gaozhou Camellia,'Huajin',Luchuan Camellia,Xianghua Camellia,'Xianglin XLC15','Yunyoucha 9' and C.hainanica were used as a rootstock for 'Haiyoul','Haiyou2' and 'Haiyou3' grafting.The survival rates of three C hainanica cultivars grafted with different rootstocks were generally above 90%,and there was no significant difference.Nine rootstocks had significant effects on seedling height,ground diameter,biomass,total root length,root surface area,soluble sugar,soluble protein and chlorophyll content of C.hainanica grafted seedlings,indicating that rootstocks affected the growth of C.hainanica grafted seedlings at the later stage.The principal component analysis was used to evaluate the seedling raising effects of different rootstocks,and it was found that the rootstocks from C.hainanica and Luchuan camellia had higher scores for 'Haiyou 1' 'Haiyou 2' and 'Haiyou 3'.3.The effects of different container sizes and types on the growth of C.hainanica seedlings.Grafted seedlings of 'Haiyou 1','Haiyou 2' and 'Haiyou 3' were transplanted into 6×7,6×10,8×10 and 8×13 cm nonwoven bags and 6×7,6×10 and 8×10 cm plastic seedling cups.The seedling height,biomass,total root length,root surface area and soluble sugar content of grafted seedlings of three C.hainanica increased with the increase of the container size;however,ground diameter,root diameter,soluble protein and chlorophyll content were less affected by container size.When the container sizes were the same,the total root length and root surface area of grafted seedlings in non-woven bag were higher than those in black plastic cup,indicating that non-woven bag was more conducive to the growth of root system of grafted seedlings.Therefore,it is recommended to use 6×10 or 8×10cm non-woven bags for C.hainanica seedling cultivating.4.Screening of light substrate formula for C.hainanica seedlings.According to the single-shaped centroid method in the design of the mixture experiment,bark,peat,coconut coir and perlite were mixed and used for C hainanica seedlings cultivation.The results showed that survival rate of grafted seedlings of three C.hainanica cultivars in single formulas such as T1(bark),T3(coconut coir)and T4(perlite)were all below 88.21%,which was significantly lower than that in mixed formulas.Seedling height,biomass,total root length,root surface area,soluble sugar and soluble protein content of grafted seedlings in T1,T2(peat),T3 and T4 formulas were also all lower.T15(25%bark+25%peat +25%coconut coir+25%perlite)and T14(33.33%peat+33.33%coconut coir+33.33%perlite)mixed formulas had the better nursery effect.In these two formulas,survival rates of grafted seedlings of three C.hainanica cultivars were higher than 93.25%;seedling height,fresh weight of scion,fresh weight of rootstock,total root length,root surface area,soluble sugar content and soluble protein content were more than 21.00 cm,4.34 g,4.43 g,466.44 cm,374.09 cm2,43.36 mg/g and 41.93 mg/g,respectively.Ground diameter,root diameter and chlorophyll were not significantly affected by formulas.Therefore,it is recommended to use T15 and T14 formulas for seedlings cultivation in C.hainanica.5.Study on the cultivation of large-size container seedlings.According to the orthogonal design for large-size seedling cultivation experiments,bark,peat,red soil and bagasse ash were used as the test factors,Analysis variance results showed that for the seedlings of three C.hainanica cultivars,seedling height,biomass,total root length,root surface area,soluble sugar and soluble protein content were significantly higher than other formulas in B8(bark:peat:red soil:bagasse=3:2:1:3)and B3(bark:peat:red soil:bagasse=1:3:3:3)formulas,,wheras ground diameter,root diameter and chlorophyll content were not significantly affected by formulas.The range analysis results showed that bagasse ash had the greatest effect on the cultivation of large-size container seedlings,followed by bark,while peat had a minimal impact.Therefore,it is predicted that the optimal large-size container seedling cultivation formula is bark:peat:red soil:bagasse ash=3:1:3:3.