New technique for producing hybrid seed

American and Belgian scientists have developed a technique for making it easier and cheaper to produce hybrid seed from any crop. Hybrid vigour can increase yields of some crops by 20% or more, so hybrid seed plays an important part in increasing food production. Hybrid seed production has not always been commercially viable. When two crop varieties are selected as the parents for hybrid seed it is necessary to remove the male organs (the anthers which produce pollen) from the variety that has been selected as the female line so that self fertilization does not take place. The seeds that are then produced by that plant will be the result of cross fertilization with the other variety. Removing or picking off the anthers by hand is easy in some crops, such as maize but it is labour intensive, for crops in which the anthers are small or inaccessible, it can be very difficult. This difficulty has seriously restricted the amount of hybrid seed available for many of the important food crops of the world, such as rice. The new technique uses genetic engineering to ensure that selected crop varieties can be made male-sterile. They will be normal in all respects except that they will not produce pollen. The lining of the anther, known as the tapetum, is crucial to pollen formation. It is through the tapetum that pollen grams are nourished with proteins and other substances. The new technique destroys the tapetum. To do this the researchers add to the plant a gene that produces an enzyme which destroys the tapetum and leads to male sterility. The basic work was carried out on oil seed rape. In theory, it should be possible to transfer the same enzyme-producing gene into any plant. If it does not work then it will be necessary to develop a gene specifically for that crop, but the researchers feel that will not be difficult now that the technique has been developed. Department of Biology University of California Los Angeles, California 90024-1606 USA Plant Genetic Systems, NV J. Plateaustraat 22 B-9000 Gent. BELGIUMAmerican and Belgian scientists have developed a technique for making it easier and cheaper to produce hybrid seed from any crop. Hybrid vigour can increase yields of some crops by 20% or more, so hybrid seed plays an important part in increasing..