Having it both ways

by Teresa Acklin
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Research leads to high protein and increased wheat yields.

   Flour millers needing high-protein wheat and growers striving for high-yield harvests soon may find their goals becoming more compatible, based on research that promises to end the frequent tradeoff between wheat yield and protein levels.

   Scientists at the Weizmann Institute of Science, Rehovot, Israel, have produced yield increases of up to 40% in some wheats — without reducing protein content. The scientists, led by Moshe Feldman, plant genetics department head at the Institute, achieved this feat through their genetic research on wild wheat.

   Wild wheat's natural protein level is twice that of cultivated wheat, Professor Feldman said recently, and research efforts focused on unlocking the wild wheat's genetic secrets. Professor Feldman and his group identified the genes responsible for the high protein, found the chromosomes containing those genes and transferred the genes to cultivated varieties of durum and bread wheat grown in Israel.

   The “new” wheat varieties were first grown and harvested in field trials near Rehovot in 1989 and 1990, and Professor Feldman said the results were somewhat unexpected.

   In a few lines, protein did jump to as high as 18% to 20%. But yields declined by 70% from the average for the same non-genetically altered variety, reflecting the negative correlation between protein and yield.

   The surprise came in the majority of the genetically altered wheat lines. In those lines, protein increased from average by a modest one- to two-percentage points. Yields, on the other hand, advanced sharply.

   For example, a genetically engineered variety of durum wheat attained a yield of 7 tonnes per hectare, which represented a 40% increase over that variety's average. Similarly, yields for the altered lines of bread wheat increased by 15%, with slightly higher protein.

   The reasons for this behavior are not yet clear, but investigations to uncover the physiological basis are continuing.

   As for the new wheat's end-use characteristics, initial tests showed protein quality was not affected. In fact, the tests indicate baking quality may be improved, he noted.

   This aspect of the project also will draw further study, Professor Feldman said. He explained that wild wheat contained 30 genes affecting protein, while cultivated wheat had just 15. Further research will try to confirm a correlation between an increased volume of protein genes and higher bread and pasta quality.

   Although the high-yield, high-protein lines are most encouraging, Professor Feldman said even the low-yielding lines might have commercial potential. Because of their extremely high protein content, those lines may be attractive to makers of cereals, granola and meat substitutes, he said.

   One final result of the research also could prove beneficial. The genetically altered wheat lines use nitrates much more efficiently than their non-altered cousins. This trait could lead to reduced use of fertilizers and chemicals, which would provide health and environmental benefits.

   The new wheat lines currently are undergoing further field trials sponsored by Israel's Ministry of Agriculture. Professor Feldman said the testing program should be concluded in about two years. At that point, the wheat will be ready for commercial distribution.

   Although the new wheat lines resulting from the research are particularly suited to the North African and Levant regions, Professor Feldman said the same genetic engineering techniques could be applied to all wheats. After testing is complete, the new lines will be offered to geneticists elsewhere for research on local varieties, he said.

   The Weizmann Institute of Science in Rehovot, Israel, was founded in 1934 by Dr. Chaim Weizmann. Its scientific staff today numbers some 1,800 researchers, engineers and technicians in a variety of scientific disciplines. The Institute also operates graduate programs for 550 students.

   Wheat research at the Institute originally was sponsored by Charles Lubin, founder of the Sara Lee Corp., to study protein content and crop yields. The Sara Lee Corp. is a U.S.-based bread and cake producer with plants in the U.S., Canada, Australia and the United Kingdom.

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