Planting uncertified trees can lead to unforced errors. By Anna Mouton.

Plant improvement is to orchard establishment what eating broccoli is to your health: boring but effective. But many growers probably don’t incorporate enough of either. Whereas we don’t have data on growers’ diets, we do know that most deciduous-fruit orchards are established with uncertified trees.

“In 2023, only 30% of deciduous trees were certified,” said Rachel Kriel, addressing participants at the 2026 Hortgro Stone-fruit Seminar and Orchard Walk. Kriel has led Plant Improvement South Africa (PlantSA) since 2017 and describes herself as passionate about high-quality plant material.

In her presentation, she explained what plant improvement is, why it matters, and how it works. While acknowledging that the system isn’t perfect, she made a strong case for why planting certified trees reduces growers’ risks.

What is plant improvement?

Plant improvement focuses on equipping growers with trees that have superior genetics, health, and quality. “Consumers want new tastes, colours, and health benefits,” said Kriel. “Without new genetics, we as South Africans will lose our footprint in the international market.”

New cultivars or clones are obtained through selection, breeding, and importation, all of which form part of plant improvement. Besides attracting the eyes, palates, and wallets of consumers, new cultivars can be better adapted or higher-yielding. But good genes don’t guarantee orchard success.

“It’s important that your trees are pest and disease-free and provide the orchard with environmental resilience and a longer lifespan,” said Kriel.

To ensure healthy trees, propagation material must be tested for known diseases of economic importance, and mother blocks and nurseries must be inspected. “Phytosanitary integrity is not only about viruses,” clarified Kriel. “It’s also about not introducing other pathogens, for instance, into your orchard soils.”

Physical and physiological tree quality is the third aspect of plant improvement. Orchards established with high-quality trees have a head start, enabling them to come into production earlier and remain productive longer, contributing to greater cumulative yields and profitability.

Given a choice, no grower would knowingly plant weak, stunted, or diseased nursery trees. When plant improvement is properly implemented, growers can opt for certified trees, thereby reducing their risk of defective or misidentified plant material.

Why do we need regulation?

Kriel discussed several reasons for regulating plant improvement, with a common thread of reducing risk and protecting our industry. Regulation also helps set standards and holds parties accountable.

“It’s important to have proof that the trees you buy can give you a high-quality crop,” Kriel told the audience. “You won’t trust a nurseryman who gives you low-quality trees, and the nurseryman won’t trust the person who provides low-quality propagation material.”

The same principle applies throughout the value chain. For example, if we don’t protect imported cultivars, the international cultivar owners won’t trust our country with their intellectual property, and we’ll lose access to new genetics.

Regulation also strives to prevent disease outbreaks, financial losses, and crop failures, and reassures our markets of our responsible and sustainable practices. Kriel illustrated the role of regulation in maintaining our markets by referring to GlobalG.A.P. certification.

“One of the boxes you need to tick for GlobalG.A.P. is that you start your orchards with certified plant material,” she said. “If you’re audited and don’t comply, it could be very negative, not only for you but also for the industry.”

How is plant improvement regulated?

In South Africa, plant improvement is mainly regulated by the Plant Improvement Act (Act 11 of 2018), which is on par internationally with the regulations of the International Union for the Protection of New Varieties of Plants.

The Plant Improvement Act provides for plant improvement schemes, the registration of premises (such as nurseries, plant improvement organisations, and laboratories), the official listing of varieties (cultivars), and the importation and propagation of unlisted varieties.

The Act also sets minimum standards for propagation material that even uncertified trees must meet to be sold.

Other relevant legislation includes the Agricultural Pests Act (Act 36 of 1983), the Plant Breeders Rights Act (Act 12 of 2018), and the Genetically Modified Organisms Act (Act 15 of 1997).

Kriel highlighted two regulations under the Agricultural Pests Act. Regulation 110 deals with the local movement of plants and plant material, and Regulation 111 covers the importation of plants and plant material into South Africa.

“Regulation R111 is critical,” she said. “The importation of plum pox into the United States is an example of how badly things can go wrong. It was first detected in 1999. Within seven years, the United States and Canada had to remove 450 000 infected stone-fruit trees. By 2006, the peach industry in the United States had lost almost EUR 5 million in direct costs due to the virus.”

The Directorate of Inspection Services within the Department of Agriculture is responsible for implementing the various acts. However, after recognising its limited capacity, the Department approached the fruit industries to assist with regulation. This led to the promulgation of the Deciduous Fruit Plant Certification Scheme in 1993.

How does the Scheme work?

The Deciduous Fruit Plant Certification Scheme is a voluntary certification scheme for deciduous-fruit trees (grapevines have a separate scheme), managed by the Deciduous Fruit Plant Improvement Association (DPA) under the direction of an executive board.

The DPA board has representation from Hortgro Pome, Hortgro Stone, the Canning Fruit Producers Association, nurseries, plant improvement organisations (SAPO, Stargrow, and TopFruit), and the Department of Agriculture.

“As many board members are also participants, the DPA cannot apply the regulations of the Scheme — it would be like marking your own homework,” said Kriel. “So, in 2004, PlantSA was registered as an independent service provider.”

PlantSA manages the Scheme on behalf of the DPA. As part of the Scheme requirements, PlantSA audits the plant improvement organisations and nurseries and inspects and certifies nursery trees. (A detailed article on their role and the Scheme appears in Fresh Quarterly issue 11).

However, Kriel is careful to emphasise that PlantSA cannot compel nurseries to certify trees or prevent the sale of uncertified trees.

“Uncertified trees fall under the jurisdiction of the Department of Agriculture. Should a grower have a problem with an uncertified tree, their only recourse is to try and get a resolution from the Department,” she said.

Of course, certification isn’t perfect. Newly emergent pests and diseases can breach the Scheme’s defences, as plum marbling demonstrated. Therefore, the Scheme is currently undergoing major revisions, and Hortgro is funding research to improve our ability to detect and eliminate diseases in plant material.

Meanwhile, growers shouldn’t dismiss the value of certified plant material. At the 2026 Hortgro Technical Symposium, a technical adviser shared a cautionary tale from the pome-fruit industry, where several growers have suffered significant setbacks after establishing orchards with nursery trees grafted on incorrectly identified rootstocks.

The purpose of certification is to prevent such unforced errors. Uncertified trees are to orchard establishment what beer and pizza are to health, but in the case of uncertified trees, the risks outweigh the rewards.