Research conducted by Bernardo O. Dizon, agriculturist of the UP BLISS Economic Garden, can enhance fruit production by 50 to 100 percent over the ordinary propagation technique.

     By using compatible rootstock and scion, double rootstock in case of calamandarin, Dizon is able to make citrus trees grow vigorously and produce fruit earlier than the usual method of using only a single rootstock, especially pummelo budded on calamandarin.

     Native pummelo growing wild in clayey, rocky soil, as in the mountains of Cagayan, is a good rootstock for Davao Pummelo.

     Dizon said that the native pummelo is a big tree with deep root system and thus drought resistant. When used as rootstock the plant grows faster and yields twice the production of plants propagated using the small calamandarin as rootstock. Calamandarin as a rootstock is susceptible to foot rot disease when planted in clayey or poorly drained soil.

     With the discovery by Dizon of native pummelo as rootstock for Davao pummelo, mountainous areas like Antipolo can now be planted with Davao pummelo, which commands a high price. Dizon said that Davao pummelo is a high income crop, which is also a possible dollar earner.

     Dizon also found that seedless oranges like Navel, Hamlin and Valencia are compatible with native pummelo rootstock.

     Seeded orange, mandarin, lime and calamansi are compatible with calamandarin rootstock, which is a small citrus tree. Calamandarin thrives well only in sandy loam or light soils. Even on sandy loam soil, there is no uniform growth. Some plants are stunted and the grower may still experience deaths even if the single rootstock is already one year old or more because of poor root development.

     To overcome this problem, Dizon uses two calamandarin rootstock by inarching the budded or grafted seedlings to another calamandarin rootstock. This method of inarching is easy. Even a person without propagation background can learn it in 10 minutes. Dizon himself teaches visitors free of charge during Sundays.

     Dizon said that two rootstocks supporting the plant accelerate its growth and development, which means early fruiting. This double rootstock affords better anchorage so the tree can withstand strong winds better.