| Grafting compatibility is the most basic standard for graft success. However, the abnormal growth characteristic occurred since some leading persimmon cultivars like ‘Fuyuu’ or ‘Taishuu’ grafted on Chinese traditional rootstock Date Plum(Diospyros lotus) which suggested immediate or delayed incompatibility. This incompatible phenomenon may result in propagation failure or weak tree vigor in orchard production. In this study, we used the grafted plants in the field as reference, the early graft compatibility of ‘Taishuu’ with “Niuyanshi†or “Xiaoguo Tianshi†were investigated based on in vitro grafting including micro-callus grafting and explanted cleft-grafting. Through observation of growth and anatomical investigation about graft union, a fast and simple technique were established for detecting the compatibility between novel rootstock and PCNA persimmon. In addition, the relationship among “Niuyanshi†and “Xiaoguo Tianshi†with their offspring were analysed by SSR molecular marker to explore their reproductive characteristics. The main results are as follows.1. In the field, ‘Youhou’ tree grew well and graft union being well developed after 45 d and one year since grafting on the rootstocks of Date Plum, “Niuyanshi†and “Xiaoguo tianshi†respectively. It suggested that ‘Youhou’ were graft compatible with Date Plum, “Niuyanshi†and “Xiaoguo tianshiâ€. The dormant buds of ‘Taishuu’ sprouted after 45 d after grafting on Date Plum, but the graft union was easily to separate and not well developed, the scion lost water to death for the bad vascular formation after one years later. However, when using “Niuyanshi†and “Xiaoguo Tianshi†as ‘Taishuu’ rootstocks, the scion plants grew well. Therefore, ‘Taishuu’ were graft compatible with “Niuyanshi†and “Xiaoguo Tianshiâ€, but not with Date Plum.2. In vitro culture experiment, explanted cleft-grafting results showed that the growth of scion of ‘Youhou’ retain well after autografting, but without new callus cells formation at the graft union. When Date Plum, “Niuyanshi†and “Xiaoguo tianshi†act as the rootstock of ‘Youhou’, during the different growth periods, the scions grew well and there were new callus cells proliferated. “Taishuu/ Date Plum†grew weaker and blackened in the graft union at different developmental stages for a vascular connection failure between rootstock and scion. ‘Taishuu’ exhibited well grafting compatibility to the “Niuyanshi†and “Xiaoguo Tianshiâ€, respectively. The results of explanted cleft-grafting are consistent with the field experiment, which indicated that explanted cleft-grafting can be used for early judging compatibility between candidate rootstock and PCNA persimmon.3. In the micro-callus grafting experiments, ‘Youhou’ callus maintain a suspending proliferation status in the four graft combination. The cells at the cutting surface conjuncted closely but without apparent new callus proliferation. Explanted cleft-grafting showed more advantage than micro-callus grafting in early judging grafting compatibility.4. There were obvious difference at DNA level between “Niuyanshiâ€, “Xiaoguo Tianshi†and their offsprings based on SSR markers after three pollination treatments. The development of seeds in “Niuyanshi†and “Xiaoguo Tianshi†need exotic pollinationIn summary, “Niuyanshi†and “Xiaoguo Tianshi†are excellent rootstock candidate for ‘Taishuu’. The explanted cleft-grafting in vitro can be used for early graft compatibility judging. The seed formation of “Niuyanshi†and “Xiaoguo Tianshi†concerned to sexual reproduction. |
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