Mariano Marcos
State University

Gamma-blasted garlic spells hope for new Ilocos varieties

By Ian Paul Villanueva

Garlic has long been dubbed the ‘white gold’ of Ilocos Norte, distinguished by its unique, pungent aroma that sets it apart from widely consumed varieties. But despite Ilocos Norte’s leadership in the country’s local production, it disparately compares to those we import from abroad.

As part of efforts to make local garlic more competitive, the MMSU Garlic Research Center (GRC) has conducted several experimental studies in hopes of breeding new, more marketable local garlic varieties. One of these is mutation breeding through gamma irradiation.

In a study by the GRC, five Ilocos garlic varieties, namely, Ilocos Pink, Ilocos White, Ilocos Tan Bolters, Mexican, and MMSU Gem, were subjected to gamma irradiation at the Philippine Nuclear Research Institute (PNRI).

Titled “Impact of gamma irradiation doses on early growth of Philippine garlic (𝘈𝘭𝘭𝘪𝘶𝘮 𝘴𝘢𝘵𝘪𝘷𝘶𝘮 L.) varieties,” and authored by Ms. Jeremay Layaoen, Ms. Noralyn Legaspi, Dr. Raymund Julius Rosales, Dr. Dionisio Bucao, Ms. Micah Benize Gregorio-Balbas, and Ms. Clarita Palacio, the study sought to evaluate the effect of certain doses of gamma rays on the early growth of the aforementioned garlic varieties.

The study primarily focused on early plant growth. In the long run, the gamma-blasted garlic cloves are hoped to eventually reproduce, several generations down the line, new garlic varieties of the ideal size, shape, and distinctive characteristics of Ilocos varieties.

While that goal is still too far ahead and to claim that it will be achieved is still premature, the GRC’s research focus has already allowed it to gain significant foundational knowledge that helps it in its ongoing pursuit.

𝗚𝗮𝗺𝗺𝗮 𝗿𝗮𝗱𝗶𝗮𝘁𝗶𝗼𝗻 𝗮𝘀 𝗮 𝗺𝘂𝘁𝗮𝗴𝗲𝗻

GRC Chief Noralyn Legaspi explained that the very nature of garlic reproduction is what limits applicable breeding techniques for the crop. Unlike other staple crops such as rice, corn, and other vegetables, breeding garlic is more complicated because it is propagated through cloning and not by the use of true seeds.

Ordinarily, crop breeding can be done through a number of ways that do not involve physically altering the DNA of the plants. In most crops that produce seeds, hybridization can be done to achieve new plant varieties by mixing and matching traits from parent plants. An example of this is cross-pollination or the transfer of pollen from one plant variety to another to produce new ones that have desirable traits.

Since garlic is cloned rather than raised from true seeds, Ms. Legaspi explained, hybridization is not possible. This is where mutation breeding via gamma irradiation comes in. 

Acting as a physical mutagen, controlled doses of gamma rays pass through the cells of the garlic cloves, gently disrupting their DNA sequences. As a result, new generations of the garlic are expected to manifest particular traits that reflect the change it has undergone at the genetic level.

𝗠𝗠𝗦𝗨’𝘀 𝗽𝘂𝘁𝗮𝘁𝗶𝘃𝗲 𝗺𝘂𝘁𝗮𝗻𝘁 𝗴𝗮𝗿𝗹𝗶𝗰𝘀

But as to what traits are observed in succeeding generations of the plant is a matter of chance. Ms. Legaspi explained that it is not possible to control which traits will manifest in the cloned garlic bulbs. 

All that the researchers could do is screen through hundreds upon hundreds of garlic bulbs to select the ideal ones, replant them, and repeat the selection process all over again until the observed deviations become stable.

Now into its fourth generation of cultivation (M4), the experimental garlic crops have moved past the initial observations and yielded some signs of success. The GRC researchers have begun observing some garlic bulbs that were bigger than usual and some that had no inner cloves, traits sought by the researchers for the new Ilocos varieties. 

Believed to have been genetically altered by the irradiation, the M4 generation of the experimental garlic plants (putative mutants, as they are technically called) keeps the pursuit of new Ilocos garlic varieties alive.

Be that as it may, it will take some more generations of cultivation before these traits can become stable enough to undergo further evaluation and eventually be registered as new Ilocos garlic varieties.

The path from a radiation chamber in PNRI to markets in Ilocos Norte and beyond is a journey that might still take years to come true. Numerous evaluations have yet to be conducted on replicated on-station and on-farm experiments to be undergone by the samples to compare them with existing varieties, not to mention the small window of garlic planting season that limits the amount of time for the cultivation of newer generations.

𝗧𝗵𝗲 𝗯𝗶𝗴𝗴𝗲𝗿 𝗴𝗮𝗿𝗹𝗶𝗰 𝗶𝗻𝗱𝘂𝘀𝘁𝗿𝘆 𝗽𝗶𝗰𝘁𝘂𝗿𝗲

According to data from the Philippine Statistics Authority (PSA), Ilocos Norte leads the country in local garlic production. The province accounted for about 74% of the country's total output in 2022. Nevertheless, such a high market share is contrasted by the fact that over 90% of annual national demand is met through imports, indicating a significant gap in the country's ability to grow the garlic it needs on its own. 

This gaping deficit is what the researchers at the GRC are ultimately trying to close, and the breeding of new Ilocos garlic varieties is only one of the solutions being considered. Dr. Dionisio Bucao, Director of Research in MMSU, explained that infestation, disease, and the changing climate remain the most pressing challenges for garlic propagation.

“Our primary goal is to develop improved Ilocos garlic varieties that are resistant to major insect pests and diseases while maintaining high productivity under changing environmental conditions, particularly fluctuations in temperature and rainfall associated with climate change,” Dr. Bucao explained. “The adoption of improved garlic production technologies has the potential to increase yields, a substantial improvement over the current average yields achieved by farmers,” he added.

Until no new viable Ilocos garlic varieties are proven to be scalable, the ones we have now will have to continue competing with foreign-produced garlic. For now, it suffices that the findings in the M4 generations keep the dream for new Ilocos garlic varieties alive.