Early Identification Of Graft Compatibility And Rootstocks Selection In Persimmon(Diospyros Kaki Thunb.)

Grafting is an ancient and now well-developed technique that is essential in modern persimmon production. However, the abnormal growth characteristic between some leading persimmon cultivars like ‘Fuyuu’ or ‘Taishuu’ and traditional rootstock Date Plum(Diospyros lotus L.) suggested immediate or delayed incompatibility and this may result in propagation failure. Therefore, it’s an important issue to survey and select compatible rootstock for leading persimmon cultivars, which will be beneficial to the sustainable development of persimmon industry. Recently, Persimmon group of Huazhong Agricultural University collected two new semi-vigorous rootstock genotypes named Xiaoguo Tianshi and Niuyanshi, which showed a good compatibility with ‘Jirou’ and ‘Matsumoto-wase’. The genetic background of both new found rootstock genotypes and their effects on leading persimmon cultivars are not well understood. In this work, we investigated the genetic relationship among Xiaoguo Tianshi, Niuyanshi and some popular persimmon cultivars with D. lotus and other 3 related species. Meanwhile, we studied micro-cleft and micro-callus grafting protocols for early detection of graft compatibility by using Xiaoguo Tianshi, Niuyanshi and date plum as rootstock. Futhermore, the field performance of the trees being six years old derived from four graft combinations were evaluated. The main results are as follows:1) The genetic relationships among 26 persimmon genotypes were determined by retrotransposon-based marker SSAP with 29 primer sets. In total, 442 scorable amplification bands were generated, accounting for 97.7% polymorphisms. Based on UPGMA analysis, Niuyanshi and Xiaoguo Tianshi grouped together with D. kaki, while D. lotus had a relatively far genetic distance with main cultivated varieties. D. lotus T from Taiwan presented a close relationship to Chekiang persimmon(D. glaucifolia Metc.).2) The experimental of two callus-grafting methods results showed vertical stacking was better than parallel stacking in callus-grafting development. From the result of micro-callus grafting, Xiaoguo Tianshi as ‘Jirou’ rootstocks would be the best one combination, followed by Niuyanshi and Date plum as rootstocks for ‘Jirou’. Meanwhile, Xiaoguo Tianshi should be excellent rootstock for ‘Fuyuu’, followed by Niuyanshi and Date plum as rootstocks for ‘Fuyuu’. Niuyanshi is recommended to be as rootstock for ‘Matsumoto-wase’ than Xiaoguo Tianshi and Date plum.3) Different miacro-grafting binding methods played an important role on graft compatible. Banding using tin foil may provide fixed and shading to graft union. Growth of ‘Jirou’/‘Xiaoguo Tianshi’ were better than using ‘Jirou’ as rootstock, while contrary for graft union development. From the histological anatomy observation of four graft combinations, ‘Jirou’ autografting was the best by comparing with ‘Jirou’/Xiaoguo Tianshi, ‘Jirou’/Niuyanshi and ‘Jirou’/ Date plum.4) The growth vigor and graft union formation being six years old derived from four graft combinations including Xiaoguo Tianshi and Niuyanshi as rootstock, ‘Jirou’ and ‘Matsumoto-wase’ for scion, which were evaluated from 2012 to 2014. Yield and fruit set percentage on Niuyanshi tended to exceed Xiaoguo Tianshi. There were no apparent significant effect of both rootstocks on scions concerning other factors such as fruit shape, seeds, SSC, etc..Those results implied that Niuyanshi and Xiaoguo Tianshi belong to D. kaki and would be good rootstock candidates for the success of persimmon propagation.