PRODUCTION OF DISEASE-FREE MOTHER TREES AND BUDWOOD OF ‘NECK ORANGE’ IN SOUTHERN THAILAND

Shoot-tip grafting (STG) in vitro was used to recover disease-free citrus for producing healthy primary budwood to develop healthy mother trees in the ‘Neck Orange’ rehabilitation program.
In our experiment, STG ‘Neck Oranges’ were 100% free from greening pathogen confirmed by PCR analysis for midribs from 20 STG plants.
In addition, the higher rate of successful STG was obtained with ‘Troyer’ citrange than with ‘Somkeawan’ mandarin or Neck Orange rootstocks.
The percentages of successful graft were 38, 19 and 5%, respectively.
Since STG ‘Neck Orange’ were still in their early stage to produce primary budwood, the mother trees for budwood production experiment were then developed from citrus tristeza virus (CTV) and greening bacterium-free ‘Neck Orange’ cuttings.
Shoots of the mother trees for producing budwood were induced by branch trimming.
The average of 36, 29.1, 19.6 and 10.5 bud sticks per tree per month were obtained by trimming the tree with 4, 3, 2 and 1 branches, respectively.
According to our results in a 6×9 m² insectproof nursery, 15 mother trees are likely to produce 3,240 disease-free buds within 6 months.
Consequently, these buds will be grafted on rootstocks to produce 2,500 healthy ‘Neck Orange’ trees at an 80% successful grafting rate.

XXVII International Horticultural Congress – IHC2006: International Symposium on Citrus and Other Tropical and Subtropical Fruit Crops

R. Sdoodee, N. Sriboonkong, Y. Sutdhikaranya

Citrus reticulate, disease free stock, tissue culture, micro-grafting, shoot-tip grafting, rootstock

https://doi.org/10.17660/ActaHortic.2008.773.5