Study On The Micrografting Techniques Of Ziziphus Jujuba Mill. In Vitro

Jujube witches' broom (JWB) is the most serious and destructive disease of Chinese jujube in China. Micrografting is becoming a new method for disease resistance inducing. A perfect system of jujube micrografting techniques is first established with 'Dongzao' plantlets for scions and 'Pozao' disease plantlets for rootstocks. Each factors influencing survival rate of micrografting are studied. In addition, successful tissue culture system of two jujube cultivars ('Nanjingdamuzao' and 'Xingguang') of high resistance to JWB and one cultivar ('Lingzao') of sensitive to JWB are established. The pilot study on disease resistance inducing of JWB and resource evaluation are carried out with the three cultivars scions and 'Pozao' disease plantlets for rootstocks .The main results are as follow:1 Establishament of multiplication system of scion cultivars:The explants from water culture can reduce contamination rate. The startup medium of 'Nanjingdamuzao' and 'Xingguang' is MS+BA0.2 mg/L +IBA0.1 mg/L;'Lingzao' is MS+BA0.4mg/L +IBA0.2mg/L. The best multiplication medium of 'Nanjingdamuzao' and 'Lingzao' is MS+BA2.0 mg/L + IBA0.5mg/L with multiplication modulus 2.8 and 2.3 respectively;The optimum multiplication medium of 'Xingguang' is MS+BA1.0 mg/L + IBA0.2 mg/L with multiplication modulus 2.4.2 Obtain of rootstocks for micrografting :After 'Pozao' disease plantlets are cultured in medium of MS+IBA2.0mg/L for 40 days, plantlets with long internode and thick stem become the appropriate rootstock for micrografting.3 Establishment of micrografting technology of jujube:The optimum culture conditions of jujube micrografting is medium with 50g/L sugar concentration and pH 6.0 . 28℃ is the optimum temperature. For humidity, the culture bottles need being sealed with cotton plug and single closure.For improving micrografting survival rate, scions without stem tip should be cut off the leaves and rootstocks should keep leaves. In addition, the optimum rooting medium of 'Pozao' disease plantlets is 1/2MS+IBA1.5mg/L, with rooting rate 85.6%. But rootstocks with roots are disadvantageous for micrografting survival rate.Using the improved micrografting method, banding with silver paper, placingvertically, micrografting survival rate can be improved.PVP can not reduce the brown rate of micrografting plantlets. 4 The pilot study on disease resistance inducing of JWB and resource evaluation:After micrografting with rootstocks from different concentration drugs for JWB and 'Pozao' scions, the infection time is delayed. Some scions are not infected.With 'Pozao' disease plantlets for rootstock and four cultivars ('Pozao', 'Nanjingdamuzao', 'Xingguang' and 'Lingzao') for scions, micrografting infection rate is 100%, 23.8%, 31.6% and 91.3% respectively.