Once BRRI completes the variety, it will give farmers respite from crop losses caused by disease
In a feat of perseverance, rice scientists in Bangladesh have achieved a rare success in developing a rice variety that effectively withstands both blast and bacterial blight.
Of the 10 major diseases that Bangladeshi rice varieties are most susceptible to, blast and blight are the most dangerous. As the names suggest, one is caused by a fungus and the other by a bacterium.
The diseases have the potential to destroy 70% of crop yields in worst-case scenarios, and they cause substantial losses for farmers in Bangladesh who grow the cereal each year.
Scientists have now combined genes that are resistant against rice blast and bacterial blight from different sources and successfully introduced them into BRRI dhan28, one of Bangladesh’s most popular rice varieties that grows even in countries beyond the national frontiers.
BRRI dhan28, with its high yield potential, usually grows well in the Boro season and is normally highly susceptible to blast and bacterial blight. Following the introgression of multiple resistance genes, scientists at Bangladesh Rice Research Institute (BRRI) have found the variety to show total resistance against both diseases.
When I asked BRRI scientist Dr Md Abdul Latif, the man behind the double resistance initiative, how his team had managed to achieve the feat, he tried his best to explain the process in layman’s terms.
“With the aim of developing the resistant variety, we took up a hybridization program to combine resistant genes (Pi9, Pb1, Xa4 and Xa21) against the background of BRRI dhan28 for the development of bacterial blight and blast resistant variety,” said Dr Md Abdul Latif, who heads the Plant Pathology Division of BRRI in Gazipur.
He added that the Pi9 and Pb1 genes had proved to be effective against blast disease, while the same was true of Xa21 and Xa4 against bacterial blight.
BRRI plant pathologists sourced these resistance genes from three different rice cultivars collected from the International Rice Research Institute (IRRI), Philippines, and Japan International Research Center for Agricultural Sciences (JIRCAS), Japan.
“Marker assisted selection was followed for combining both blast and bacterial blight resistant genes to develop the resistant variety. In each generation, genotyping and phenotyping were done to select the best plant carrying blast and bacterial blight resistant genes,” explained Dr Md Abdul Latif.
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He added: “After consecutive crosses and selection, fixed lines carrying resistant genes were developed.”
The BRRI has already field-tested the doubly resistant lines at 12 different locations across Bangladesh and happily found that the resistant lines remained disease-free, while other varieties suffered.
Dr Latif hoped that BRRI would now proceed with a regulatory compliance process for varietal release so that farmers could benefit from the resistant variety.
The BRRI scientists developed the resistant lines under a Program in Agricultural and Life Sciences (PALS) funded by Bangladesh Academy of Sciences – United States Department of Agriculture (BAS-USDA).