Population structure of pyricularia grisea and reaction of rice cultivars in the Southern Highlands of Tanzania
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Date
2014
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Publisher
Sokoine University of Agriculture
Abstract
The study was designed to investigate the diversity of Pyricularia grisea (Coke)
Sacc, population structure and reaction of rice cultivars in Southern highlands of
Tanzania.
Screen house experiments and a field trapping nursery were used to
determine prevalent pathogenic races, effective host resistant genes and reaction of
rice cultivars against identified pathogenic races. A total of six pathogenic races
Ull-i2-kl41-zl3-tal03, U51-i4-kl00-zl 3-tal 03, U11-i4-k041-zl 1-tai03, Ull-i5-
k000-z03-ta000, U11-iO-kl01-zl3-tal00 and U11 -il-k!20-zl l-tal02 were identified
on the basis of the infection type of LIJIANGX1NTUAN HEIGU (LTH) monogenic
lines. Pathogenic race U1 l-i2-k 141-zl3-tal03 was the most virulent strain infecting
44.4 % of the tested varieties, followed by U51-i4-kl00-zl3-tal03; Ull-i4-k041-
zll-tal03; U1 l-il-kl20-zl I-tal02; U1 l-i0-kl01-zl3-tal00 and U1 l-i5-kOOO-zO3-
taOOO infecting 40.7, 37, 37, 33.3 and 14.8 % of the tested varieties, respectively.
Host resistance genes PH2, Piz-t, Pill, Pik-rn, Pi 12, Pia, and Pik-p were found
effective against the available pathogen races. All local varieties tested were
susceptible to all races identified differing only on the levels of susceptibility. Uyole
inbred lines (UR 319 and UR 400) were susceptible to all races except race U1 1 -i5-
kOOO-zO3-taOOO and race U1 l-i4-k041-zl1-tai 03. The races identified provide an
insight of blast population diversity prevalent in Southern highlands that should be
considered when breeding for blast resistance. Effective resistant genes identified
can be pyramided to Uyole inbred lines and in commonly grown local susceptible
rice varieties to improve blast resistant against prevalent races in Southern highlands.
Description
Dissertation
Keywords
Population structure, Pyricularia grisea, Screen house, Southern Highlands, Tanzania, Pyricularia grisea (Coke)