The sugarcane industry is huge in the Philippines, with many other industries heavily dependent on sugar, such as the energy and fuel sectors including bio-ethanol.
In fact, according to a March 31, 2016 article in Inquirer.Net, sugarcane farming is the second most in demand job in the Philippines, the first time in recent history that this has happened in local agriculture. The article cited data from the Bureau of Local Employment indicating that as of January 2016, there were 12,400 vacancies for sugarcane farmers and 100 job openings for sugarcane grinders.
Then Department of Labor and Employment Secretary Rosalinda Baldoz claimed that this could be attributed to the stable sugar prices in the global market.
Therefore, the sugarcane industry along with its allied industries should be supported to sustain this strong demand, especially considering the fact that like any other crop, sugarcane deteriorates, becomes prone to disease and its yield decreases as it remains in the field.
To sustain the industry’s growth, new and superior varieties of sugarcane should be developed, according to Dr. Liwayway M. Engle of the Philippine Sugar Research Institute (PhilSURIN).
The problem is, sugarcane breeding which includes marker assisted selection of promising varieties, is a long and tedious process – taking as many as 8 to 9 years – thus requiring a lot of human and financial resources. The process is long due to sugarcane’s long life cycle and complex genetic nature which requires huge breeding populations of 100,000-400,000 genotypes.
To solve this problem, Engle said that genetic improvement of sugarcane must be continuously undertaken. Speaking at the recent S&T Agri Biotech Forum held at the Bureau of Soils and Water Management Convention Hall, Engle stated that sugar genomics is good for increased productivity, profitability, sustainability and global competitiveness of the Philippine sugar industry.
Organized by the Department of Science and Technology (DOST)-Philippine Council for Agriculture and Aquatic Resources Research and Development, the forum was part of the activities for the 12th National Biotechnology Week held last month.
Engle and her team which includes a pathologist, agronomist, and breeders, started a project in 2012 that sought to apply genomics in sugarcane variety development. For this, PhilSURIN partnered with the Philippine Genome Center, whose state-of-the-art DNA sequencing facilities were funded by DOST.
The objective was to reduce the time it takes to develop a new variety by 2-3 years, thus shortening the process from 8-9 years to 5-6 years, “so we can bring new varieties to sugarcane planters a lot quicker,” Engle said.
In particular, the group wanted to produce high-yielding varieties while eliminating their susceptibility to two major diseases affecting sugarcane through DNA marker assisted selection (MAS). These two diseases aredowny mildew and smut.
MAS is a process in which scientists search for biomarkers associated with a particular trait. When a marker is found to be consistently associated with a specific trait, that marker may now be used by the scientists to screenfor that trait. Biomarkers therefore help speed up the development of new sugarcane varieties.
Under the conventional 8 to 9-year breeding program, there are two stages where selection against diseases is done.
For screening of downy mildew, the team selects the best in terms of morphological traits among the 100,000 varieties they produce. These selected ones are subjected to a screening procedure so they can see which of them are resistant against the disease. They are planted and laid down in mildew nurseries where there are also susceptible varieties. Then inoculation is done where the inoculum (water containing downy mildew pathogens or agents which cause downy mildew) is sprayed on the seedlings. After this, evaluation is undertaken so the team can discover which of the varieties selected are resistant to downy mildew.
For screening of smut, the planting materials are soaked in the inoculum containing the smut pathogens after which incubation is done. Then the planting materials are planted in the field and the team awaits the growth of the seedlings. The team then rates the plants on whether they are susceptible or resistant to smut.
Hence, to shorten the process, Engle’s team decided to undertake the project particularly on application of biotechnology for marker assisted selection.
In identifying the markers for these diseases, they collectsamples of sugarcane at the right age - about 3-6 months. These samples are ground and genomic DNA is isolated from the samples. The DNA then undergoes amplification or multiplication into several duplicates. The material is then subjected to electrophoresis, a technique for separating the components of a mixture of charged molecules in an electric field. Through electrophoresis, different band patterns consisting of different segments of DNA may be seen. Band patterns are also called DNA fingerprints. This data is then analysed and they compute for genetic distance which determines how similar or how different the two sugarcane parents are. This information is useful to the scientists in deciding whether to cross pollinate or hybridize the two parents. Next, they do analysis or association test for the trait that they are considering for the marker. Then they score the band patterns for each variety, to know which band pattern exists in which varieties and which band pattern is unique to a certain variety.
These band patterns or DNA fingerprints are also used in variety integrity tests to check the authenticity of the sugarcane variety, after which a certification is issued. This will ensure that farmers are planting the right variety in their fields.
Previously, a variety may only be identified via its morphological and agronomic characteristics, after it has produced enough stalk and it exhibits the characteristics unique to this variety.
So far, Engle and her team has already ranked the different promising sugarcane varieties based on field trials in Victorias City and La Carlota in Negros Occidental, and in Bukidnon. They hope to eventually produce five promising varieties.
Other partners for the project are the Sugar Regulatory Administration and the National Institute of Molecular Biology and Biotechnology of the University of the Philippines.
