Browsing by Author "Jomanga, Kennedy Elisha"

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    Effects of rice yellow mottle virus disease on performance of rice genotypes
    (Sokoine University of Agriculture, 2014) Jomanga, Kennedy Elisha
    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.