Breakthrough against potato disease

By JAMES LARAKI
THE farming community now has the opportunity to trial new potato varieties after the National Agricultural Research Institute (NARI) officially made a preliminary release of two varieties resistant to late blight.
The varieties, referred to as NP1 and NP2 (NP stands for NARI potato), were pre-released during the agricultural innovations show early this month along with a broiler feeding system and two cold tolerant rice varieties for the highlands.
Smallholder farmers, who had been unable to grow the crop after it was wiped out by the potato late blight (PLB) disease in March 2003, would welcome the preliminary release of the two varieties.
The potato industry, worth about K25 million then, had not recovered fully because the common variety, Sequoia, was still susceptible to PLB.
After the outbreak, caused by fungal agent Phytophthora infestans, the Sequoia variety could not be grown by ordinary farmers due to the cost of weekly fungicide treatments. The Sequoia is highly susceptible to late blight and potato production had been limited to a relatively small number of commercial farmers who could afford chemicals, backpack sprays and potato seedlings.
Subsistence farmers, particularly in the highlands, had relied on potato. It was not only a commercial crop but a source of food next to sweet potato (kaukau), particularly in the high altitude highlands where the choice of staple food was limited.
In a view to revive the industry, particularly with smallholder farmers in mind, NARI initiated a project in 2003 with funding support from the Australian Centre for International Agricultural Research to evaluate blight resistant varieties.
The objectives of the project were to introduce, multiply, evaluate and deploy late blight resistant clonal material into PNG and to develop safe and cost-effective integrated late blight management strategies for existing and new potato cultivars and, ultimately, to rehabilitate potato production for smallholders.
Under the project, NARI sourced 59 international potato centre (CIP) clones in 2003 and evaluation work were undertaken at various sites to assess late blight resistant and yield. Of the 59 clones, 12 were selected and further evaluated against Sequoia on-station and on-farm.
The two varieties pre-released had proven to be late blight resistant, high yielding and have other favourable agronomic traits such as good taste and processing quality. These were observed through on-farm farmer participatory trials covering 15 sites over three seasons in Enga, Western Highlands, Chimbu, Eastern Highlands and Morobe.
The pre-released varieties were supplied to a wide range of farmers and the public for their comments and views, both at the growing and harvesting stages.
Many farmers had approved and were into growing them, including seed production.
The Enga rural potato project, based in the Lagaip-Porgera district, had ventured into seed production with a view to reviving the crop locally and throughout the province.
This was a good initiative as the adoption of new potato varieties by farmers depended on the availability of a consistent supply of quality seed potatoes.
The late blight disease remained a concern to potato farmers, especially in the highlands where the crop is grown.
The fungus is a specialised pathogen of potato and is an extremely destructive disease of potatoes.
It attacks both tubers and foliage at any stage of development and is capable of rapid development and spread.
It was responsible for the devastating Irish potato famine of the 1840s and had continued into the present.
Since the Irish famine, late blight became the most studied potato disease in the world.
Previously, free of the disease, PNG was one of the world’s few remaining safe havens for growing potato until 2003. The entire potato crop was wiped out in a matter of weeks after it was first discovered in the Sirunki area of Enga.
Late blight was believed to have come across from the neighbouring Indonesian province of Irian Jaya.
Yield losses caused many smallholders, who relied on potato as a valuable cash and food crop, to withdraw from production leading to an increase in potato prices in the country.
Some breakthrough had been made to control PLB using fungicides, however, the extra input had been a burden to smallholder growers.
Therefore, identifying suitable varieties was the long-lasting solution to revive the potato industry.
NARI, with support from other partners, had taken on this responsibility and the preliminary release of the two varieties was an outcome of efforts to assist smallholder growers revive the once-thriving industry.
It was hoped that smallholder farmers would now grow their favourite crop once again.
The preliminary release of the blight resistant varieties was a breakthrough against the devastating potato disease and it was now up to the farming community to try the varieties and adopt them.