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Overview of quality control

Provides a draft overview of quality control in sweetpotato seed practices Explains objectives and structure of FAO technical guidelines for Quality Declared Planting Material.

Quality control

A key challenge which sweetpotato agriculture research for development is trying to address is how to ensure that farmers have timely access to quality planting material.

However, who defines quality, and who manages quality? Who validates that a certain quality has been achieved and who pays for that quality control or inspection service? Is the additional cost of quality control compensated by increased root yields from better quality planting material?


Certified seed or quality declared seed?

An on-going discussion concerns the appropriateness of formal seed certification for sweetpotato. The formal functions of seed certification and standards which are normally carried out for grain crops by the public or private sector are generally not implemented for vegetatively propagated crops (VPCs).


Farmer based seed practices for sweetpotato

Farmer based seed practices operate on the basis of farmer’s own tacit knowledge of selection of planting material. Farmers who become locally recognised as sources of planting material, build their reputation based on the characteristics and quality of their material. However, generally we have a very limited understanding of how farmers perceive “quality” and how those perceptions influence their willingness to pay for planting material.


Quality assurance

If quality is being checked or monitored it is most likely done for institutional buyers, before material is harvested and distributed from secondary and or tertiary sites. This inspection is normally done by the researcher/NARO with participation by a representative of the buyer and representative of the farmer/group/association buying the vines.


FAO guidelines for quality declared planting material

FAO has produced technical guidelines on protocols and standards for Quality Declared Planting Material (QDPM) of VPCs (FAO, 2010).



The guidelines are based on the recommendations of a consultation with highly qualified experts.  Similar to Quality Declared Seed (QDS) QDPM is a quality assurance scheme for seed production. It is less demanding than full quality control systems and thus, can be more easily implemented in situations where resources are limited. The standards and protocols are targeted at seed producers and technicians at the community level and also for national seed services and the agricultural research community.

The goal of the QDPM process is to raise the physiological and phytosanitary quality of the plant reproductive materials available to smallholders and as a consequence to increase agricultural production and productivity. It is meant to be implemented primarily by seed producers at community level or field extension workers.


Reference: FAO, 2010. Quality Declared Planting Material. Protocols and standards for vegetatively propagated crops. FAO Plant Production and Protection Paper 195. FAO, Rome.

About Margaret McEwan

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