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We’re as passionate about glasshouse growing and rootstock utilisation as you are, and we’re therefore excited to be able to share with you the complete story behind De Ruiter™ rootstock. Our newly released book titled ‘Your roots of success’ (click here for your electronic version) details the history of De Ruiter’s rootstock program, grafting techniques, rootstock varieties and outlines just how De Ruiter™ is responding to glasshouse grower’s changing demands.  Our unrivalled glasshouse expertise stems from our strong heritage of innovation and leadership within the rootstock market, contributing to improved resistance to stress conditions and better fruit quality.

High performing De Ruiter™ varieties provide outstanding growing potential so you can deliver your harvest to market with pride.

 

Learnings from Holland – Komeett versus Merlice (DRW7812)

Merlice (DRW 7812) is starting to conquer the global market and rightly so, since this variety has many benefits.
For the two companies of Van der Knaap in Monster and Honselersdijk, Philip van der Knaap grows two De Ruiter™ tomato varieties successfully: Komeett and Merlice (DRW 7812). In Honselersdijk, he has grown Komeett for the second consecutive year on six hectares [about 15 acres]. In the greenhouse in Monster, they have started growing Merlice for the first time.

Philip says, “We come from a long line of vegetable growers and therefore have a preference for a variety that is somewhat more generative. In that respect, Komeett is more generative than Merlice. In Monster, we have a co-generation (simultaneous production of electricity and heat) power capacity of 0.6 megawatts per hectare. In Honselersdijk, we have a co-generation power capacity of 0.7 megawatts per hectare with two motors. We can play around very effectively with the CO2 supply. Komeett responds very easily to CO2; we look at the leaf position every day and go by that. With Komeett, you have to make sure you do not give it too much when the weather is bad. Then we scale way back on the CO2!”

Steady growth

“Komeett is a large variety with outstanding quality of fruit. The benefit is that Komeett already has heavier fruit early in cultivation. Komeett starts at about 130 grams and increases to fruits of 170 to 180 grams. We grow this variety in a cool, steady manner so that we constantly keep a strong crop.” First year of Merlice Van der Knaap is starting this year for the first time with Merlice. Philip’s faith in this variety is so great that he immediately planted the entire greenhouse with it, partly because this is easier to manage. Philip says, “I have seen tests of Merlice in Belgium and with other growers. Merlice has tremendous potential. The quality is good and the fruit is a good size. They keep a nice shine and there are no less than five extra fruits per stem than with Komeett. The average fruit weight is also greater and the tomato is not susceptible to splitting. Merlice has a full crop with extensive leafing.”


Mildew resistant

“The biggest advantage of Merlice is the mildew resistance. Merlice is not susceptible to blight. We still use sulfur for a few hours every other day, but we do not need to spray at all.” Philip says about the fruit: “Unlike Komeett, Merlice has somewhat less heavy fruit in the beginning. At the first harvest, we are talking about 100 grams or so but that can quickly increase to 180 grams. But honestly, I think we should have cultivated it more generatively in the beginning, and then the first fruit would have been somewhat heavier. That is a lesson for the next crop.”