摘要
The development of the science of cytology and genetics, particularly on cell structure and function provided a breakthrough for breeders and allowed for early selection. Character of stomata density on some commodities was reported as important factor to determine the disease resistance. The research was done for getting information about the differences in the stomata characters influenced on the level of Vascular Streak dieback （VSD） resistance on cocoa. The research was conducted in the Laboratory of Genetics, Gadjah Mada University and leaves samples were conducted in Kendeng Lembu Gardens, PTPN XII. The research used a split plot design with three factors included the type of clones with different levels of VSD disease resistance （PA 191, BL 703 and GS 29）, leaf position （top, middle and base） and leaf age （young and old）. Stomata characters included number of stomata, stomata opening width, stomata wide and stomata diameter were observed. The results showed that the stomata characters in three cacao genotypes with different resistance levels indicated a difference in number of stomata, stomata size, stomata opening width, stomata wide and stomata diameter. Stomata number, stomata opening width and stomata diameter on PA 191 （resistance clone） were lower than the susceptible clones （BL 703 dan GS 29）. The lowest of number and diameter stomata on the base position on the old leaves tissues. Number of stomata, stomata opening width and stomata diameter were estimated role in mechanism of VSD resistance and that were expected could be used as criteria selection to VSD resistance.
