Study finds corns resistant to Fusarium ear disease

  • 10 April 2015, Friday

Source: BusinessMirror
28 Mar 2015

TWELVE corn varieties and inbred lines showing resistance to ear rot caused by the fungal pathogen Fusarium have been identified after 43 white corn lines/populations and lagkitanwere screened in a study conducted by the University of the Philippines Los Baños (UPLB). Among these lines or genotypes, three exhibited potentially most resistant, which will be subject to further confirmatory tests.

These potential lines can be used as donor in developing resistant varieties of white corn, according to the Department of Agriculture (DA) Biotechnology Program, which provided funds for the research. Fusarium ear rot is a common corn disease that is more widespread in tropical and subtropical regions.

Data from the UPLB-Institute of Plant Breeding (UPLB-IPB) indicated that during the 2007 wet season, 35 percent of ears harvested was infected with the pathogen and the degree of infection ranged anywhere from 5 percent to 60 percent. Efficient breeding strategies for disease-resistant white corn varieties are viewed to be beneficial to local corn industry since corn is the second most important crop in the Philippines.

Dr. Gil C. Saguiguit Jr., director of the Southeast Asian Regional Center for Graduate Study and Research in Agriculture, said the findings would be a big boost to the corn industry. He said that recent estimates placed the number of Filipinos consuming white corn as their main staple at 14 million.

Using biotechnology, the study also resulted in the development and validation of a reliable detection method for corn. Using this method, the researchers have confirmed what has long been suspected: distribution of the ear rot pathogen is widespread in corn-growing regions in the Philippines.

The study used samples from all over the country collected in collaboration with the DA regional field office, local government units, and state universities and colleges. The results of a two-year study by a UPLB research team led by Dr. Cecilia Pascual and Dr. Eureka Teresa Ocampo were reported in the paper “Fusarium ear rot of maize: Fumonisin-producing Fusarium species and host resistance” presented during the 2014 Annual Meeting of the Phytopathological Society of Japan.

Hopefully, their findings will contribute to existing efforts to develop resistant corn varieties, improve detection of the pathogen and develop effective control mechanisms for the disease. The widespread occurrence of fusarium ear rot in different regions in the country is a cause for concern, particularly in areas where the pathogen cannot be detected readily and the infected corn may still enter the food chain and affect consumers and livestock.

Some species of the pathogen produce fumonisin, a family of mycotoxins, which can cause serious animal and human diseases, including esophageal cancer and neural tube birth defects in humans and lethal horse disease and porcine pulmonary edema among animals. The most predominant fumonisin-producing Fusarium species causing Fusarium ear rot in the Philippines is F. verticillioides.

Two other species, F. proliferatum and F. graminearum, were also present in specific areas but in less than 1 percent of the total isolate collection.

Preliminary results of the study based on the physical traits and genetic diversity of the ear-rot pathogen suggest that it is highly diverse and able to adapt under local conditions, suggesting a high possibility of the rapid evolution of resistance against the current control measures such as application of fungicides. Increased humidity, hot weather and drought conditions favor the proliferation of Fusarium.