RE SEARCH Salt tolerance studied in depth development of a potato crop’, the breeder emphatically adds. ‘Saline soils usually have also to cope with a poor soil structure, which results in other problems such as mineral shortages and soil diseases. We take that into account when developing salt-tolerant varieties. One such symptom is susceptibility to scab. A variety grown on seepage soil will often be confronted with that.’ Always salty near Saefthinge As the trial location in Zierikzee was too prone to fail because of the lack of seepage water in wet seasons, Meijer started to look for areas where the soil is always salty. They found one also in the province of Zeeland, in the south-western part near the Belgian border. On the border of the very salty Saefthinge nature reserve (the ‘Flooded land of Saefthinge’), close to the village of Nieuw-Namen, Jean-Pierre van Wesemael has an organic farm on which he grows potatoes and vegetables. He specialises in the cultivation of salt marsh crops such as sea lavender, marsh samphire and for a few years now, salty potatoes. Van Wesemael markets these potatoes as Saefthinge Zilt (Salty Saefthinge). For the plot on which he cultivates his salty crops, he transports salt water via a pipeline straight from the salt marshes outside the dike. So, this plot is always saturated with saline water. ‘And that’s ideal to carry out our potato trials’, Heselmans tells us. Parallel-trial in Egypt Last year, breeding company C. Meijer B.V. started a long-term period of variety research trials. Parallel to these, trials were also started in Egypt, where the seed potato sector also markets varieties for consumption potato growers, who farm in the middle of the desert. ‘Crop expansion and yield increase mean that more water is needed every year. Because they’ve been pumping up water from the water pits for years, the water level has dropped to great depth. The deeper you get the more Because the Egyptians have been pumping up water from the water pits for years, the water level has dropped to a great depth. The deeper you get, the more saline the water. saline the water, because it’s right in the middle of the salt layers. On the basis of the desert images, Heselmans shows that the differences in salt tolerance among the varieties can be enormous. ; We’re also testing here with drip irrigation varieties with a range of salt values.’ Study into deeper causes The object of the trials is to select varieties that show little or no yield and decreased quality under saline conditions. A few varieties already posses that characteristic. Yet, this isn’t the only spearhead. ‘Meijer is a modern breeding company and also looks into the deeper causes of variety characteristics. Genetic knowledge provides the fastest result, and this requires the biggest budget for research costs now and later. So we’re trying to find out which gene or genes are responsible for the various characteristics. In addition, we’re literally trying to dig up any connection there might be between drought, heat and salt damage. We really think that we’ll be making great leaps forward in the coming years. We’ve got a modern laboratory with DNA marker technology at our disposal and an extensive gene bank. To be able to supply sufficient food in the coming years and to solve the increasing shortage of fresh water, it’s important that we discover the secret behind salt stress tolerance as soon as possible. By bringing back potato cultivation to saline agricultural land, we’ll be helping to tackle these problems. At the same time, saline land that’s never seen a potato will be available for the production of food’, Heselmans argues. ● Leo Hanse If there is a shortage of rain, the capillarity of the clay soil can cause the seepage to rise and reach the root zone of the potato plants. Potato World 2013 • number 4 35 Pagina 34
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