Effects of rice yellow mottle virus disease on performance of rice genotypes
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Date
2014
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Sokoine University of Agriculture
Abstract
Screen house experiments were conducted at Sokoine University of Agriculture
during the season of 2011/12, to investigate the reaction and effect of Rice Yellow
Mottle Virus (RYMV) disease on rice genotypes. Virulence among the three RYMV
strains S4, 5 and 6 were tested. Disease reaction was observed on 1-9 scale. Results
of pathogenicity test indicated that strain S5 was the most virulent strain followed by
S6 and S4. Kalalu (resistant variety) was similarly affected by S5 as susceptible
varieties. In experiment two and three, 52 rice genotypes were inoculated with
RYMV strains S4 and S5, in order to identify rice genotypes resistant to RYMV
disease. Results based on symptoms and grain weight indicated that eleven (11) rice
genotypes were resistant/tolerance to RYMV disease. Grain weight reduction ranged
from 1.01 to 43.69 %, while disease severity score of 1 to 5 were observed. These
eleven rice genotypes were IR 73886-9-2-4-1-1, IR 71605-2-1-5-3-4, IR 69705-1-1-
1-4-2, IR 71028-3-1-2-5-1, IR 71029-3-1-5-5, Matata Gl, IRR 134, Matata G2, IR
69704-4-4-4-8-1-1-1, Adday Sei and IR 71027-43-3-2-B-3. Thirty seven (37) rice
genotypes were susceptible, including SARO-5 and Supa (susceptible controls). The
decrease in plant height and grain weight due to RYMV disease ranged from 12.01
% to 63.66 % and 48 % to 86 % respectively. The effect of RYMV disease on
number of tillers per plant, showed both increase and decrease in tillers produced
among inoculated genotypes. Therefore, future field research should focus on testing
identified resistant rice genotypes against RYMV strain S5.
Description
Dissertation
Keywords
Rice genotypes, Disease reaction, Rice Yellow Mottle Virus (RYMV)