National persimmon varietal evaluation program 2018-2023 (PR17000)

There have been four rootstocks established so far. Three at grower’s properties in Mildura (Victoria), Gatton (Queensland) and Sydney (NSW), and one at the NSW DPI Dareton Research Institute. The trials are very young; therefore no production data is available at this stage. It is expected that the first crop will be in June 2023 and the yield and quality data will be collected on the three trial sites.

Diospyros lotus rootstock seedlings have been developed with a tissue culture method successfully. There have been 600 rootstock seedlings produced by the clonal propagation methods. This was the first time that the Diospyros lotus rootstock has been produced in Australia. The Diospyros lotus seeds were imported from Spain in 2019. The five mother trees of Diospyros lotus have already been established at NSW DPI, Dareton for future seed sources.

These current rootstock seedlings were grafted in October 2022 to establish experimental trials at the grower’s properties and at the NSW DPI research station. The trees will be planted at the three trial sites in October 2023. Taishu (an early maturing variety) was imported from Japan in November 2020. The variety was in quarantine for almost three years, only recently being released. Three trees are now growing in pots at the Dareton Primary Industries Institute. The limited amounts of budwood were used to graft rootstock seedlings in October 2022. The trees will be used to establish a mother block for future budwood sources.

Progress on uniformity work (clonal propagation)
So far, the Diospyros lotus rootstock seedlings have been developed with a tissue culture method (Figure 1). There are 600 rootstock seedlings produced by the clonal propagation methods. This was the first time that the Diospyros lotus rootstock has been produced in Australia. The Diospyros lotus seeds were imported by Dr Tahir Khurshid (NSW DPI) from Spain in 2019. The mother trees of Diospyros lotus have already been established at NSW DPI, Dareton for future seed sources.

These current rootstock seedlings will be grafted in October 2022. The trees will be planted at different trial sites in October 2023. The participating growers have been contacted for the establishment of the trials at their properties.

Update on new scion and rootstock material from overseas
Taishu (an early maturing variety) was imported from Japan in November 2020. The variety was in quarantine for almost 3 years, only recently being released. Three trees are now growing in pots at the Dareton Primary Industries Institute. The limited amount of budwood will be used to graft rootstock seedlings in October 2022, which will be used to establish a mother block for future budwood sources.

Other varieties planned to be imported:
Early maturing South Korean varieties will also be imported to Australia. Dr Khurshid visited Pear and Persimmon Research Institutes in Naju, South Korea in October 2019 and inspected the varieties. At this stage, South Korea is arranging to import the new varieties into Australia, however, this work has been significantly slowed down with Covid-19.

Update on grower’s trials
There have been 4 rootstocks established: 3 at grower’s properties in Mildura (Victoria), Gatton (Queensland) and Sydney (NSW), and one at the NSW DPI Dareton Research Institute. There were two rootstocks S2 and G1, which are the local selections of Diospyros kaki and ‘Jiro’ scion variety is grafted to these 2 rootstocks. The trees were planted in September 2020 and there is no fruit production expected from these trees until May 2023.

Update of genotypic/phenotypic for existing ‘Rojo Brillante’
A formal contract has been signed between NSW DPI and IVIA to exchange rootstock material. Therefore, IVIA will be able to send hybrid rootstocks to Australia soon.

Project Reference Group Meeting
The project reference group meeting is planned for July/August 2022. During this time growers are not too busy, and their harvest season is completed.

Spain and Portugal, major producers of persimmon, were visited in late 2018 to gather information on different aspects of persimmon production. Sites included research and academic institutes, persimmon orchards, packing facilities, storage facilities, ripening facilities, and persimmon nurseries.

The visit allowed collaboration to be established, with Dr Maria Badenes from IVIA (the Valencia agriculture institute) now formally linked to this project, and links made with the University of Algarve, also in Spain.

The research team reports that the visits furthered their work, including…

• Learning about a Spanish pruning system that allows overseas producers to produce persimmons without investing in trellis supports. The branches within the trees are tied up with strings to bear the fruit load during the growing season. To test the system in Australia, a new planting at Dareton will trial the technique.
• Arranging the importation of Diospyros lotus seed from Spain, which will proceed once phytosanitary arrangements are made and clearance is gained from the Australian Government.
• DNA from the Australian selection of Rojo brilliante, a major persimmon variety grown in Spain and Portugal, will be tested to confirm that it is, in fact, that variety. Rojo brilliante has an upright growing habit and will be evaluated for commercial production in Australia.

Other progress includes…

• Collaboration with experts in Japan, China and South Korea has benefited the project, offering the possibility of importing new varieties into Australia.
• Collaboration with plant nurseries to develop stock for grower trials.
• Progress on clonal propagation.
• The establishment of two trials with growers, one in Renmark South Australia and the other in Collignan Victoria, which make use of existing rootstock.
• Collaboration with nurseries to raise rootstock seedlings.