Abstract:

Xanthomonas wilt disease
devastating disease of birw
known resistant banana to this
known resistant banana to this :?"
one wild type, A/zz.syz
K •,-npala. Uganda
cl biological sciences, U • ¦ •
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initially migrated beyond the point of inoculation, Xvm populaGon did not build up had its
presence was restricted to the inoeLiiatcil and the immediate follower leaves which subsiquently
wilted and died in some plants. The pathogen population within piani tissues was observed to drop
in a 50 mg tissue from 3.06x107cfu at 18days after inoculation in the inoculated leaf to 1.5xl04cfu
by the 12lh week after inoculation in the immediate follower leaf and later to 0 efu by the 20th
week after inoculation in other follower leaves. In contrust lo the same size of tissue in the
susceptible cv "Nakinyika" its population increased from 3.41x10s to 1.08xl0"cfii within 3 weeks
after inoculation. In addition, bacterial migration within M. balbisiana was slow, where it took up
to 12 weeks to be detected as far as only the immediate follower leaves. In the susceptible cv
“Nakinyika” Xvm migration was faster and it had spread to adjacent leaves within 2 weeks after
inoculation. Consistent with the decreasing bacteria! population and limited migration, initial
symptom development was also delayed, only first observed in the inoculated leaf at 10 weeks
after inoculation. In addition, the incidence and severity of wilt remained low at 33% and 20%
respectively and with the exception of the individual wilted leaves that subsiquently died, the
plants were never broken down but continued to grow without anymore symptoms.
Key words: Banana plantlets, resistant, tissue colonization, Xanthomonas vasicola pv. Musacearu