Test growing

Conducting a test growing trial (which may include a comparative growing trial) is an essential step in applying for plant breeder's rights for a new plant variety.

Who conducts a trial and why

You and your technical adviser (qualified person) are responsible for all aspects of the comparative growing trial.

The results of the trial are used to determine whether your new variety is distinct, uniform and stable (DUS).

Which varieties to compare

You choose which varieties to compare in the trial, but you must include the most similar varieties of common knowledge.

If it's the first variety of a species

In a trial for the first named variety of a species, you need to compare the new variety with one or more well-known existing forms of the same species with similar characteristics to the new variety.

How many plants

The number of plants of each variety to include in the trial depends on the propagation method. The UPOV technical guideline for the species tells you how many plants to include and may also recommend how many replications.

If there isn't a UPOV guideline

If there isn't a UPOV technical guideline for the species, follow the general rules below, but note that you may need more plants to show uniformity.

cloned ornamental and fruit tree varieties:

  • at least five, preferably 10, plants of each variety
  • treat each plant as a replica

cloned horticultural and vegetable varieties:

  • 30 to 60 spaced plants of each variety
  • divide into two or more replicas

self-pollinating, seed propagated varieties:

  • 30 spaced plants of each variety and generation
  • divide into three replicates of 10

partly self-pollinated, seed propagated varieties:

  • 30 to 60 spaced plants of each variety and generation
  • divide into two or more replicates

open-pollinated, seed-propagated varieties:

  • 100 spaced plants of each variety and generation
  • number of replicates depends on plant type  


A comparative trial in Australia may not be necessary if the variety has been test-grown in a UPOV member country using official UPOV guidelines and test procedures and all similar varieties of common knowledge have been included in the trial. We still require breeders to submit a detailed description of the variety for publication in the Plant Varieties Journal.

More information

Last Updated: 28/11/2013

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