mb.com.ph; March 8, 2014

Due to high market demand for purple yam or ube, the Department of Agriculture (DA) aims to increase yam production in the country by mass-producing plantlets through tissue culture.

Purple yam, scientifically called Dioscorea alata, or locally known as ube, is one of the high-value crops in the country given its export potential and the various processed products, which can be made out of it.

“At present, there is a high market demand for it whether domestic or for export. However, the production of yam is very seasonal. You can only produce it once a year,” said professor Villaluz Acedo of the Philippine Root Crops Research and Training Center (PhilRootcrops) of the Visayas State University (VSU) in Baybay City, Leyte.

A declining trend in ube production has been observed with output dropping to 15,799 metric tons (MT) in 2012 from 30,074 MT in 2006, the Bureau of Agricultural Statistics (BAS) said.

Acedo explained that tubers cannot be germinated immediately after harvest due to dormancy, which usually takes about three to four months after harvest.

“With conventional planting, farmers usually reserve 20 to 40 percent of their harvest to be used as planting materials for the next season,” Acedo said.

To increase the production and availability of yam during off-season, PhilRootcrops-VSU initiated a project titled, “Improvement of Yam Production System through Tissue Culture Derived Plantlets and Microtubers and Breaking Tuber Dormancy for Continuous Production of Planting Materials”.

Funded under DA-High Value Crops Development Program (DA-HVCDP) through the Bureau of Agricultural Research (BAR), the project aims to increase yam production in the country through mass production of viable plantlets using tissue culture techniques and to address seasonality by improving techniques in breaking tuber dormancy.

From years of field trials, it was gathered that tissue-cultured plantlets can only yield an average of 600 grams of tubers per plant.

This is mainly due to the absence of tuber piece in the plantlet as in the case of conventional planting materials with only 150-200 grams per tuber piece, which serve as food reserve to support growth of the developing sprouts.

However, recent commercial planting trials by farmers in Davao and General Santos City using tissue-cultured plantlets as starting planting materials reveal more promising average yields as it increased to 1.5 kilograms (kg) to 2 kg per plant.

Trials are now being undertaken to increase the survival of tissue-cultured plantlets in the field as part of the project.

Through the micropropagation technology, they further found out that microtubers can be produced by plantlets maintained in vitro or an artificial environment outside the living organism.

One plantlet can produce several microtubers, which can serve as both a source of micropropagules and as initial planting materials for field planting.

The presence of even a small tuber piece in the planting material produced through this method is thought to increase field survival of tissue-cultured plantlets.

Another significant component of the project is on improving the techniques for breaking the dormancy of ube to enable planting at any given month and thus spread ube production throughout the year instead of the traditional growing season from June (field planting) to December (harvesting).

“With the breaking of tuber dormancy, yam can be planted anytime of the year. Thus, production can be programmed depending on the market demand,” Acedo said. (by Ellalyn De Vera)

Source: DA to boost yam production