Population structure of xanthonionas oryzae pv. oryzae and rice cultivar resistance in three regions in Tanzania
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Date
2014
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Publisher
Sokoine University of Agriculture
Abstract
This study determined the pathogen population structure and the reaction of rice cultivars
against Xanthonwnas oryzae pv. oryzae. Field trapping nurseries were established at
Dakawa, Bunda and Kyela and inoculations for pot experiment were conducted at
Agricultural Research Institute-Uyole from December, 2012 - July, 2013. Twenty two rice
cultivars obtained from Agricultural Research Institute-Uyole and twenty one near isogenic
lines from AfricaRice Program, Dar-es-Salaam, Tanzania were arranged in a completely
randomized design and randomized complete block design in screenhouse and field
experiments, respectively. Nineteen isolates of the pathogen were obtained from the study
areas and used for physiological and biochemical tests. Data on incidence and severity were
subjected to analysis of variance (ANOVA). Duncan's Multiple Range Test was used to
separate means. Six pathotypes namely; TK3CD, TK4E, TM2C, TM2B, TB2F and TB5A
were identified frorfi the presumed nineteen isolates of the pathogen. Results showed that
IR-BB4 and IR-BB52 were resistant to Xanthomonas oryzae pv. oryzae with significantly
(P = 0.05) low disease incidence (8.18 % and 6.72 %) and severity (0.5 cm and 0.65 cm),
respectively. IR-BB 14 was highly susceptible with 61.55 % disease incidence and 6.12 cm
disease severity. The cultivars Domo la Fisi, Rangi Mbili, Tule na Bvvana, Jicho la Samola,
Rufiji, SARO 5, Mtalima Wangu, Zambia and Supa showed intermediate resistance
compared to the IR24 (control). The IR-BB4 and LR-BB52 are therefore, possible promising
rice lines that can be incorporated into rice breeding programs in Tanzania.
Description
Dissertation
Keywords
Epidemiology, Symptomatology, genetic resistance, Rice cultivars