Evaluation of bacterial blight resistance in marker assisted selection (MAS)-bred rice lines against Philippine isolates of Xanthomonas oryzae pv. oryzae

Issue Date

6-2017

Abstract

Bacterial blight (BB), named as one of the most destructive rice diseases, can cause yield loss ranging from 74-81% in severe conditions. The pathogen, Xanthomonas oryzae pv.oryzae (Xoo), infects the xylem of the rice causing lesions and eventually leading to plant death. One of the breeding strategies employed in the development and improvement of crop with durable disease resistance is marker-assisted selection (MAS), which facilitates the introgression of pyramiding of various resistance genes in a plant. In this study, 13 promising MAS-bred rice lines introgressed with Xa4 alone, Xa4+Xa7, or Xa4+Xa7+Xa21 BB resistance genes were evaluated for reactions to three most virulent Philippine Xoo races (Pxo-99, Pxo-79 and Pxo-347) under screenhouse condition. Rice plants at maximum tillering stage were artificially inoculated with Xoo through dipping method. Statistical analysis revealed that rice lines introgressed with Xa4+Xa21 or Xa4+Xa7+Xa21 exhibited high level of resistance against the three Xoo races, comparable with the resistant check IRBB64 which carries Xa4+Xa5+Xa7+Xa21. The combination of at least Xa4+Xa21 has prevented expression of any signs of BB infection, as well as on the grain appearance. Meanwhile, the presence of Xa4 alone did not enhance the plant resistance against any of the three Xoo races used. Apparently, relying on Xa4 alone may no longer be very helpful but when Xa4 is combined with another Xa resistance gene, the effectiveness can still be very promising. The MAS-bred rice lines developed will undergo preliminary yield trial this coming wet season. This study once again has proven the usefulness of MAS in the development of BB resistant rice.

Source or Periodical Title

Transactions of the National Academy of Science and Technology

ISSN

0115-463X

Volume

42

Issue

1

Page

101

Document Type

Article

College

College of Agriculture and Food Science (CAFS)

Language

English

Subject

Oryza sativa L.; Rice disease and pest resistance

En – AGROVOC descriptors

ORYZA SATIVA; BLIGHT; DISEASE RESISTANCE; GENETIC MARKERS; BREEDING METHODS; GENES; SELECTION; PROGENY; XANTHOMONAS ORYZAE

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