Caption: Meteyufa farmers happily harvesting the PT Trial
By DORCAS HOMARE of NARI
Sweet potato or kaukau farmers at Meteyufa village near Goroka were proud harvesters of improved kaukau yields of a research trial planted from clean planting materials developed through a new technology known as pathogen testing.
The trial, by the National Agricultural Research Institute’s Highlands Regional Research Centre at Aiyura, Eastern Highlands, which was planted late last year, had both pathogen tested (PT) and non-pathogen Tested (NPT) planting materials.
The comparative trial was conducted to demonstrate the advantage of PT materials over non-PT materials in terms of yield differences.
PT materials are planting materials of kaukau that are tested to be clean from diseases such as scab and scurf, but most importantly viral diseases.
Viruses are microscopic pathogens and are systemic.
They thrive in the plant from generation to generation and silently contribute to yield decline, a problem which could be overcome by the use of the PT materials.
In 2008, a PT scheme was established in PNG to improve sweet potato yield and quality by removing virus and virus-like organisms.
The PT scheme includes germplasm maintenance, foundation seed production, reselection, heat treatment, meristem culture, virus indexing using indicator plants, Enzyme Linked Immunosorbent Assay (ELISA) and/or molecular methods. In removing viruses from the plant, the PT scheme also frees plants from other diseases such as scab and scurf and pests like gall mites and weevils whose eggs are deposited on the vines and leaves.
The PT comparison trial at Meteyufa was part of an ACIAR (Australian Centre for International Agricultural Research) funded project which is investigating the impact of pests and diseases on sweet potato in PNG cropping systems.
NARI and the Fresh Produce Development Agency (FPDA), PNG, are collaborating with the Queensland Department of Primary Industries and fisheries (QDPI&F),
As part of field demonstration of the technology to farmers, FPDA, through mini field demonstration trials, has distributed more than 500 PT cuttings to farmers for cultivation at various sites in both the Eastern Highlands and
Meteyufa village is an agriculturally dynamic area in
Sweet potato is one of the most-dominant commercial crops the village cultivates.
A Meteyufa commercial farmer, Aku Ulo, noticed yield decline in his sweet potato farms and expressed it in 2009.
In response, NARI and FPDA set up the comparative trial at the village to demonstrate that planting of PT materials can help improve his kaukau yield.
The trial, which lasted about four months, was harvested on Dec 15, 2009.
Fifteen farmers from the village as well as president of the Eastern Highlands Women in Agriculture (WiA), Margaret Seko, and another member of the group, Jennifer Kena, participated in the harvest and witnessed improvements that can be derived from the PT technology.
They observed huge yield differences.
One of the farmers, Tom Soles said there were obvious differences between the PT and non-PT tubers in their shapes, sizes and general yield.
He said he was astonished to see much better yields from PT materials as compared to those by non-PT materials.
With excitement, other farmers requested for PT materials to be distributed.
The trial was hailed a success as it achieved its goal of demonstrating the advantages of the PT technology to the farmers.
From the preliminary results, it is envisaged that the project is likely to result in higher productivity through increased overall yield, improved tuber shape and flesh colour, resulting in greater market appeal.
Currently, the PT project is in the phase of cleaning up all the commercial sweet potato varieties from the Eastern Highlands and
The cleaning process is undertaken at the NARI tissue culture laboratory in Aiyura.
After the cleaning process, the clean materials will be re-introduced to the farmers for cultivation.