Courgette growers can depend on continued innovation from Rijk Zwaan

Although Rijk Zwaan has only had courgette varieties in its assortment since 2017, the vegetable breeding company regards it as an important crop. In line with its clear ambition to launch courgette varieties with added value for growers, the company introduced varieties with New Delhi resistance in 2021, much to the relief of producers in southern Europe. ″Our mission is to innovate,″ says Alessandro Silvestrelli, Rijk Zwaan’s Crop Manager Courgette. Here, he and his colleague Gabriele Lippi, Crop Coordinator, provide a glimpse of which other innovations growers can expect.

A versatile crop in all respects

Courgette – also known around the world as squash or zucchini – is one of the top five vegetable crops. This versatile and multicoloured vegetable is cultivated across the globe, whether outdoors, in tunnels or in greenhouses. Courgettes are produced for both local consumption and as an export product. Its versatility extends to how it is prepared and used; the courgette can be cooked and eaten in all manner of ways, and is suitable for frying, stuffing, barbecuing or being turned into soup or even low-carb spaghetti. ″Such an important vegetable simply has to be part of our range, so it was only logical that we decided to invest in developing our own varieties around a decade ago,″ says Silvestrelli.

Adding value throughout the chain

The company has set the bar high for itself, according to his colleague Gabriele Lippi, Crop Coordinator. ″Although we only entered this market a few years ago, our ambition is to introduce agronomically strong varieties with new traits. After all, innovation is in our DNA. It’s about including traits that create value throughout the chain, such as labour-friendliness, a longer shelf life and a total package of resistances so that growers can use fewer crop protection agents. Another focus is on varieties that can cope with climate change. Everything revolves around helping courgette growers to improve their profitability.″

Introduction of Delhi Defense

One good example of that is how Rijk Zwaan offered growers a unique solution in 2021 by introducing courgettes with Delhi Defense. This protects against infection with the Tomato leaf curl New Delhi virus (ToLCNDV or ‘New Delhi virus’), which is transmitted by whitefly. Lippi: ″The virus has been a big headache for growers, particularly in the Mediterranean region, for the past seven years, causing up to 80% of production to be lost and also negatively affecting the product quality. This is made extra problematic by the sustained activity of whitefly due to the ever-longer summers and milder winters.″

Demonstrable value of resistances

Since the launch of the first two Delhi Defense varieties, Perseverance RZ and Draconis RZ, a rising number of growers of protected crops are switching to these varieties. ″Having completed a year of successful production, growers have experienced for themselves just how valuable this resistance is. It is often the only way for them to stay in the market. We are now receiving lots of enquiries, not only from growers in Spain and Italy, but also from other courgette production regions such as France and Morocco,″ says Lippi.

Delhi Defense for white courgettes and open-field crops too

Those first two green courgette varieties have since been followed by other varieties, Silvestrelli explains: ″This year we’ve additionally introduced the green Orbiter RZ and the white courgette Kinzica RZ for indoor production. White courgettes – which are actually light green – are primarily cultivated in the Middle East, North Africa and Turkey. There is lower pressure from New Delhi there, which is why we also displayed innovative white courgette varieties without this resistance at the spring demo in Egypt.″

Additionally, Rijk Zwaan is working on open-field courgette varieties both with and without Delhi Defense. ″In 2024, we will be launching a strong open-field courgette variety, while at the same time we are also working hard on an open-field courgette variety with New Delhi resistance. Because of the outdoor cultivation method, insects such as whitefly are impossible to manage. The longer summers and milder winters are leading to greater pressure from diseases and pests. In fact, growers in regions such as Sicily have been forced to completely stop producing courgettes. In such situations, resistances are the only option,″ states Lippi.

Making varieties easier to work with

Rijk Zwaan’s innovation efforts extend beyond just Delhi Defense. Labour-friendliness is another trait that is high on the agenda due to the current worker shortage faced by growers. Lippi: ″That’s why our indoor and outdoor varieties all have an open structure and small leaves, so that employees can immediately see the fruits in the plant. Moreover, it’s easy to harvest the courgettes with your bare hands, without requiring any tools. This doesn’t only save harvesting time, but also prevents the spread of viruses.″

According to the Crop Coordinator, the new open-field courgette varieties scheduled for launch in 2024 will have another innovative trait. The plants will have short internodes and compactness, enabling them to withstand strong winds and retain an upright habit for nine weeks. ″That results in high-quality fruits, which is good news for growers and everyone else in the chain.″

Longer shelf life

Other aspects that receive continuous attention during the breeding programme are fruit quality and shelf life. ″Fruit quality is an important trait for an export product like courgette. Both internal and external testing has demonstrated that Rijk Zwaan varieties retain their freshness, colour and shine for longer,″ explains Lippi. Moreover, the existing varieties do not mark the end of Rijk Zwaan’s breeding work when it comes to courgettes, states Crop Manager Silvestrelli: ″Growers can depend on us to continue to introduce innovative new varieties that address the challenges they face and add value. That’s how we are sharing a healthy future for this crop.″