T.L. Rosario
Garlic (Allium sativum L.), onion, and shallot (Allium cepa L.) are very important crops in Asia. A number of strains, cultivars, and elite lines are grown in Indonesia, Thailand, and Philippines for local consumption and export. In the Philippines, garlic is grown mainly in Northern Luzon and onion in Central Luzon, both crops being mainly propagated asexually. A genebank for these crops should be established for their maintenance and evaluation for future use in breeding programs.

A collaborative network of vegetable research (AVNET) joining Indonesia, Malaysia, the Philippines, and Thailand was established through AVRDC with germplasm exchange as one of its subnetworks. The main objective of the subnetwork was the mutual exchange and evaluation of vegetable germplasm, including garlic and shallot. The Institute of Plant Breeding in the Philippines was identified as the lead agency to conduct the research. The institute had been collecting germplasm of the two crops, both locally and internationally, prior to AVNET. Collections of garlic from long-day countries did not produce bulbs; maintenance was a problem and these accessions have been lost.

Table 1 lists the accessions of shallot and garlic from Indonesia and Thailand. The plant and bulb characteristics of the shallot accessions including those from the Philippines and Cambodia are described in table 2. The bulb size ranged from small to medium and most were purple. Two accessions from Indonesia and two from the Philippines produced the highest number of bulblets per hill. One important feature was the flowering ability of the accessions. This characteristic plays an important role in the maintenance of the accession, as well as in its potential for crop improvement. So far, only Sumenep from Indonesia and an accession from Cambodia did not produce flowers.

Shallot, a native multiplier onion in the Philippines, has undergone some selection by farmers, and the original strain, Batanes, may be found in remote farming areas and occasionally in research institutions. Although mainly propagated vegetatively, flowers and seeds are produced. Since they are highly cross-pollinated, there is a chance for crop improvement, and selection for better clones has been practiced by farmers in the field. The multiplier onions have other desirable characteristics such as high pungency and longer postharvest life.

The plant and bulb characteristics of the different garlic accessions are shown in table 3. Except for Chiangmai, they are mostly white with medium to large bulbs. The LV series from Indonesia (table 1) did not store well, and after a year only the smaller and less vigorous LV 1020 survived. Seven accessions of garlic from the Philippines were evaluated in the 1990–91 season (table 4). They did not differ significantly in size of bulbs but varied slightly in leaf characteristics. The Batangas strain from Tanauan had good storage quality.

In vitro culture of garlic and shallot for their rapid propagation has been undertaken by Indonesia and the Philippines, the latter having developed the technology at the Institute of Plant Breeding, but the performance of the plantlets outside the culture bottles has yet to be evaluated.

Somaclonal variation occurs in quite a high frequency among tissue-cultured plants. Such events in regenerated plants should be carefully monitored by researchers.

Rosario, T.L. (1994). ALLIUM GENETIC RESOURCES IN THE PHILIPPINES. Acta Hortic. 358, 169-172
DOI: 10.17660/ActaHortic.1994.358.27

Acta Horticulturae