Research has shown that rootstock that has been inoculated with beneficial mycorrhizal fungi have a higher success rate.
I was thinking about this while reading through this thread on how difficult it is to graft mangosteen, it seems logical that one of the reasons is the poor root structure of mangosteen.
The report posted earlier of innarching a G. xanthochymus by Mike-T makes complete sense, in that article it explains success by using a dual rootstock, also at Dizons site it also mentions using the dual rootstocks technique.
Now this is just an idea, but, if you can innarch a mangosteen before
grafting, I believe you will have more success.
Now getting back to mycorrhizal fungi, one has to expect that in Thailand the soil used is teaming with symbiotic bacteria and mycorrhizal fungi.
I went searching to see if i could find any possible research done on this, and came across this report;Mangosteen (Garcinia delicious fruits of Malaysia and has great potential for commercial development. However, the long juvenile period resulting from the extremely slow growth of the seedlings renders itself an unattractive propcsition for cultivation on a large scale. Accelerating the growth rate of mangosteen seedlings is therefore an important prerequisite for the extensive commercialisation of this crop. Poorly developed root system characterised by unbranched, coarse and lack of laterals strongly correlated to the slow growth. Such root characteristics offer great opportunity for colonisation by arbuscular mycorrhizas (AM). The main objective of this study is therefore, to promote seedling growth through symbiotic associations between AM fungi and mangosteen roots. Results of inoculation studies have shO'Ml that mangosteen seedlings responded to AM infection with more than 60% of the total root length being infected. Introduced AM fungi caused tremendous improvements in the plant growth. Total dry biomass was 40%-64% and net assimilation rate was 30%- 40% higher than the uninoculated seedlings. AM inoculated plants also had 20%-40% more leaves that give 35%-65% greater leaf area compared to the uninoculated seedlings. Stomatal resistance, transpiration rates and chlorophyll content were also Significantly improved by mycorrhizal infection. Improvements in plant growth were primarily due to greater uptake of immobile nutrients, particularly phosphorus (P), zinc (Zn) and copper (Cu). Phosphorus, Zn and Cu uptakes by mycorrhizal plants were 67%-88%, 50%-93% and 53%-59% greater than the uninoculated plants, respectively. Colonisation Significantly induced greater root length density (RLD), root branching density (RBD) and number of root tips with RLD, RBD and number of root tips of AM plants ranged 58%-87%, 20%-30% and 22%-25% respectively greater compared to the uninoculated seedlings. Mycorrhizal rnangosteens were also more tolerant to water stress. They CQuid maintain higher stomatal conductance and photosynthesis at lower moisture status suggesting lower leaf water potentials at which stomata closes. Such ability indicates a more efficient stomatal regulation by AM plants
I think the key here is to get the rootstock vigorous enough to take a graft, whether it be by inoculating the roots, inarching, or a combination of both.
from Dizon's site:
to Bear Fruits Initial Fruiting Commercial Fruiting Habits
Seedling 10 feet 10 years 15 years and above Biennial
Double rootstock 10 feet 6 years 10 years and above Prolific
Grafted 1 - 3 feet 1 - 2 years 15 years and above Biennial
Double rootstock 1 - 3 feet 1 - 2 years 8 years and above Prolific
An Agronomist in the DR, told me he had good success getting his trees to start fruiting, using this fertizer http://www.swissgrow.com/product_bioforte.html
I noticed that the only thing special in it is proteins, in the above manual it is mentioned that yeast is used on seedlings which helps them grow better. so there must be something to all this, maybe the yeast/proteins help feed the beneficial fungi or help develop the roots some other way.