Philsurin, UP-DOST develop disease-resilient sugar varieties

MANILA, Philippines – The Philippine Sugar Research Institute (Philsurin) and the Philippine Genome Center (PGC) are developing promising “superior”varieties of sugar that are expected to boost productivity of the country’s sugarcane farming sector.

Philsurin’s Liwayway Engle said the availability of DNA sequencing at the PGC located inside the University of the Philippines-Diliman campus in Quezon City has allowed them to identify superior varieties of sugarcane and develop a new hybrid variety.

Like any other crop, sugarcane deteriorates, becomes prone to disease and its yield decreases as it remains in the field.

The process of sugarcane breeding and marker assisted selection of promising varieties is a long and tedious process that takes eight to nine years, and also requires huge breeding populations of 100,000 to 400,000 genotypes.

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, it may be used by scientists for screening.

Biomarkers help speed up the development of new sugarcane varieties. 

As early as 2012, Engle and her Philsurin team of researchers which include a pathologist, agronomist, and breeders, have 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 high-yielding varieties while eliminating their susceptibility to two major diseases affecting sugarcane: downy mildew and smut.

The objective is to reduce the time it takes to develop a new variety by two to three years, thus shortening the process from eight to nine years to five to six years.

In identifying the markers for these diseases, they collect samples of sugarcane aged three to six months.

These samples undergo amplification or multiplication into several duplicates. The material is then subjected to electrophoresis, a technique that separates the components of a mixture of charged molecules in an electric field.

Through electrophoresis, different band patterns consisting of different DNA segments may be seen. Band patterns are also called DNA fingerprints.

Data are analyzed to compute for genetic distance to determine how similar or different the two sugarcane parents are. 

This information is useful to the scientists in deciding whether to cross pollinate or hybridize the two parents.  They do analysis or association test for the trait they are considering for the marker then they score the band patterns for each 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 farmers are planting the right variety in their fields.