Fruits of their labors

Researchers use cutting-edge technology to breed new varieties of produce.

fall fruit harvest 88 (photo credit: )
fall fruit harvest 88
(photo credit: )
Luscious lychee. Since 1990, the yield has increased from 500 kg. to two tons per dunam. The festival of Shavuot is often referred to as the Festival of the First Fruits because of the mitzva for farmers to bring the first yields of their harvest to the holy city of Jerusalem. The ancient custom celebrates native Israeli fruits such as grapes, figs, dates and pomegranates. Today Israel boasts a medley of fruits from these biblical varieties as well as new produce brought from exotic lands. Biting into "Lemon-melon" one experiences an exotic taste of mango, sweet and acidic. A project started 15 years ago at the Volcani Institute, the melon is in its final stages of preparation and is scheduled to be available in supermarkets within two years. The "Tomaisin," a raisin tomato that dehydrates on the vine, was developed in a classical breeding program using a wild species as a donor for the dehydration trait, and has an intense taste much like tomato paste. A new variety of apricot that has yet to be named ripens as early as late April - beating the common variety of the fruit by more than a month - and should give Israeli farmers a lucrative advantage in local and European markets. Projects such as these are considered the ultimate success at the Volcani Institute at Beit Dagan - the research arm of the Agriculture Ministry - whose goal is to improve growing methods for Israeli farmers. Researchers at the institute work to develop new varieties of fruits and vegetables and solve some of the toughest problems facing agriculture. One of the biggest challenges researchers at the Volcani Institute face is how to breed new agricultural products without using biogenetic engineering, the process of creating new plants by transferring genes from different species. "Most of our markets - mainly in Europe - are against genetically engineered products," says Prof. Yoram Kapulnik, head of the Institute of Plant Sciences at the institute. This poses a problem for growers in Israel because, although transgenic fruits and vegetables could provide some advantages such as protection from viruses and delayed ripening, it would be inefficient to grow unmarketable products, he explains. "Pollen is difficult to contain," Kapulnik explains. Therefore, Israeli agriculture is almost entirely free of genetic engineering, with some exceptions where growers must apply for licenses to grow these transgenic crops. Despite this, significant research at the Volcani Institute is dedicated to molecular biology and genetic engineering, as researchers anticipate that transgenic foods will find a significant place in the market in the future. One field of research is developing plants that are naturally resistant to insect attacks, thereby allowing farmers to grow their crops without using pesticides. "We are trying to keep up with the most advanced research," says Dr. Amnon Lers, a researcher in the Postharvest Science Department. Most research, however, is conducted using traditional methods. Much of the efforts at the Volcani Institute is directed toward redeveloping ancient strains of fruits. The Israel Gene Bank established in 1979 on the Volcani campus provides an extensive collection of seeds for researchers to work with. Its fruit tree collection consists of some 150 varieties of almond, plum, peach, apricot and apple trees, plus clones of fig, pomegranate and grapevine, originated from orchards and vineyards dating to ancient Israelite agricultural systems. Due to their biblical ties, fruit trees are assigned special significance at the Volcani Institute. "Of the seven species, five were trees," says Dr. Eli Tomer, the former head of the Institute of Horticulture. "There's an awareness of a connection to the land," says Dr. Ari Schaffer, past head of the Vegetable Research Department, "even though agriculture as a way of life isn't as common [today]." Ancient Israelites enjoyed pomegranates, figs, almonds, dates, and even apples. Modern additions to the flora of Israel include peach, citrus, new varieties of apple, and more recently lychee, mango and avocado. Mango and avocado, introduced to the country in the 1930s and not grown for commercial use until the 1970s, have become a celebrated agricultural success story. Agricultural techniques have allowed for an early growing season, and the avocado and mango are exported to Europe where they are in high demand. Lychee, at first grown for noncommercial use due to its low yield of around 500 kg. per dunam, caught the attention of Volcani researchers in 1990. They brought the trees' yields to a manageable yield of two tons per dunam, mostly consumed domestically. "You can't just bring trees from foreign countries and grow them here. You need 10 years of research or more," says Schaffer, explaining that non-native trees have to be optimized for the Israeli climate. Mango, brought from India, has been bred to a succulent mild flavor, sweet, smooth and fiberless fruit, which is more accepted in Europe's markets. The "Naomi" mango, grown in the South, was developed by Tomer himself and produces a heavy yield each year. The recently developed "Sheli" mango has been planted on 2,000 dunams in the North. "And there are more [strains] on the way," says Tomer. Another exotic success is the guava, which was brought to the country almost 100 years ago. While it was a hit on the domestic market, it was impossible to export the guava because of its short shelf life and strong aroma. However Volcani researchers took on the task and created a mild-smelling, longer-life guava that was exported for the first time last year. The first-time guava exportation was accepted by the European market and growers expect an even higher demand in coming years for the "King" guava. ONE APPROACH used to develop new varieties is to look for ancient, primitive and rare fruit and vegetable varieties with novel traits and cross-breed them with modern plants using cutting-edge technology. These ancient varieties are grown from heirloom seeds preserved in gene banks around the world, and from clippings from naturally growing old trees. By looking at ancient remains found at archeological sites, scientists know which specific varieties were grown in biblical times. "One of the strategies of agricultural research is to take the progenitors and use them," says Schaffer. After an ancient species is cross-bred with a modern variety, its traits are tracked using molecular technology to produce a fast and efficient method. The process takes a long time, he explains, and projects started decades ago are just now beginning to generate results usable for the market. It's not just a trial and error approach, he says; it's a very calculated process using modern technologies such as molecular strategies similar to those used in modern medicine. But while traditional cross-breeding is time-consuming, this "intelligent breeding" using modern techniques has streamlined the process. The end results, some of which are made available for the public in Hebrew language and agricultural publications, give Israeli growers new commercial varieties to sell in domestic and foreign markets. Tomatoes are another juicy example of the work done at the institute: scientists brought in wild species and cross-bred them with the modern tomato. Using classical cross-breeding, scientists have created one variety of tomato with a high sugar content. They cross-bred wild types of naturally sweet tomatoes found in Peru with modern varieties and were able to transfer its sweetness to create the "Tasty" tomato. The Volcani Institute is a vertically integrated operation that prides itself on addressing problems from end to end. In the case of the pomegranate, one of Israel's most beloved crops, the institute developed a machine that deseeds the complex fruit, a technology that could be used both commercially and by the end consumer. But a tough examination of the marketability of the healthful pomegranate, which contains high levels of antioxidants, showed another problem: the plant flowers only once a year, which confines the season to a short period. An ongoing research program in the Fruit Tree Department is taking on this issue in an attempt to create a plant that will blossom three times each year. Combined with storage techniques and deseeding methods, researchers hope to enable Israeli farmers to tap into the full potential of the fruit. Ever adapting to new trends, another problem researchers at the Volcani Institute are tackling is how to improve seedless varieties of grapes, watermelons and other crops despite the fact that the fruits don't contain fully developed seeds. The answer lies in pulling together techniques similar to those used in modern medicine to raise seed embryos in laboratory conditions. This molecular strategy involves rescuing embryos from the soft tissue of underdeveloped seeds and raising them under laboratory conditions. "People really want to stick with the seedless fruits, and we can help serve them," says Kapulnik. The Volcani Institute boasts one of very few research centers with a department dedicated solely to issues affecting fruits and vegetables after they are harvested. The Postharvest Science Department addresses a spectrum of issues: how the produce looks, packing and shipping methods, and retaining healthy nutrients to keep up with high standards in the European market. "The atmosphere in which fruits and vegetables are put in after harvest has an effect on them," says Lers. Lers and other scientists are exploring methods to heighten various fruits' tolerance to chilling techniques; there have also been breakthroughs using non-harmful yeast to ward off fungi. One project is focused on developing sophisticated plastic that would create an ideal atmosphere to inhibit both ripening and decay. Dr. Nehemia Aharoni, another post-harvest researcher, has collaborated with an Israeli plastic company to create a material that "breathes in" ideal amounts of carbon dioxide and oxygen. The unique performance of the film, combined with elimination of condensed water inside the packaging, prevents produce decay, which is useful for perishable fruits and vegetables intended for long-distance shipping. Even though the Volcani Institute's main focus is to improve agriculture in Israel, the innovations and technology coming out of its laboratories show benefits beyond the country's borders. Volcani researchers work together with scientists in Morocco in a USAID-funded project to improve the almond industry there. The country faces decreasing species of almonds because of severe drought conditions and urbanization. "We established a project with our Moroccan counterparts to preserve seedlings of almonds," says Sara Spiegel, associate director for international cooperation. The project also involved transferring virus-detection techniques from Israel to Morocco in 2000, and introducing more efficient growing methods. "Despite a lot of difficulties due to the political climate, it's done very well," Spiegel reports. "There's an exchange of information and an interaction between scientists from different politically oriented countries. We really became good friends." Producing the future The off-season advantage Researchers at the Volcani Institute have developed a variety of quality apricot that ripens as early as late April, beating the common variety by more than a month. The research, headed by Dr. Doron Holland, should give farmers a lucrative advantage in local and European markets. The fruit boasts a long shelf life and tasty flavor, the institute reports. Healthy amounts of anti-oxidants Scientists at the Volcani Institute took a hard look at a new variety of plum called the "Red Heart" developed by fruit breeder Sefi Ben-Dor, and found that it contains very high levels of anti-oxidants compared to other fruits grown in Israel. The study, headed by Prof. Joseph Kanner of the Department of Food Sciences, showed levels of anti-oxidants in the fruit were three times those of pomegranates, and five times the levels found in apples, bananas and red wine. Self-dehydrating vine tomatoes A tomato project started 15 years ago identified the gene that causes a certain type of tomato to actually dry on the vine. The "Tomaisin," raisin tomatoes that dehydrate and have a concentrated tomato taste, were developed in a classical breeding program using the wild species as a donor for the dehydration trait. The Tomaisins Company is producing these natural vine-dried tomatoes and is currently being grown commercially. "Once we understand the biology of this tomato, we can then begin to think about what can make a grape lose its water to become a raisin," says Kapulnik.